Codon-optimized polynucleotide-based vaccines against human cytomegalovirus infection

ABSTRACT

The invention is related to polynucleotide-based cytomegalovirus vaccines. In particular, the invention is plasmids operably encoding HCMV antigens, in which the naturally-occurring coding regions for the HCMV antigens have been modified for improved translation in human or other mammalian cells through codon optimization. HCMV antigens which are useful in the invention include, but are not limited to pp65, glycoprotein B (gB), IE1, and fragments, variants or derivatives of either of these antigens. In certain embodiments, sequences have been deleted, e.g., the Arg435-Lys438 putative kinase in pp65 and the membrane anchor and endocellular domains in gB. The invention is further directed to methods to induce an immune response to HCMV in a mammal, for example, a human, comprising delivering a plasmid encoding a codon-optimized HCMV antigen as described above. The invention is also directed to pharmaceutical compositions comprising plasmids encoding a codon-optimized HCMV antigen as described above, and further comprising adjuvants, excipients, or immune modulators.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. application Ser. No. 13/525,814, filed Jun. 18, 2012, which is a continuation application of U.S. application Ser. No. 13/013,752, filed Jan. 25, 2011, now U.S. Pat. No. 8,278,093, issued Oct. 2, 2012, which is a continuation application of U.S. application Ser. No. 11/892,020, filed Aug. 17, 2007, now U.S. Pat. No. 7,888,112, issued Feb. 15, 2011, which is a continuation application of U.S. application Ser. No. 10/738,986, filed Dec. 19, 2003, now U.S. Pat. No. 7,410,795, issued Aug. 12, 2008, which claims benefit of U.S. Provisional Application No. 60/435,549, filed Dec. 23, 2002, all of which are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

Human cytomegalovirus (“HCMV”) infects between 50% and 85% of adults by 40 years of age (Gerson A. A., et al., in Viral Infections of Humans, Evans A. S. and Kaslow, R. A., eds., Plenum Press, New York, N.Y. (1997)). Although HCMV infection is benign in most healthy adults, it can result in deadly pneumonitis, as well as colitis, esophagitis, leukopenia, and retinitis in transplant and other immunocompromised patients, especially those with HIV. In solid organ transplant (SOT) or hematopoeitic cell transplant (HCT) populations, HCMV disease can occur either from new infection transmitted from the donor organ or HCT, or can recur as a result of reactivation of latent virus in the recipient.

Despite licensed therapies, HCMV-associated disease remains severely debilitating and life-threatening in HIV patients and the allogeneic related HCT and SOT settings. In addition, HCMV is the most common intrauterine infection in the United States, and results in death or severe sequelae in over 8,000 infants per year. For these reasons, HCMV was ranked in the list of the top 10 vaccines most in need of development in the United States (Vaccines for the 21^(st) century: a tool for decision making, National Academy of Sciences (1999)).

Existing therapies include the use of immunoglobulins and anti-viral agents such as ganciclovir and its derivatives, which are most effective when used prophylactically or very early during infection in at risk populations. However, these therapies are characterized by significant toxicity and limited efficacy, especially for late onset disease (onset after the first 100 days) (Fillet, A. M., Drugs Aging 19:343-354 (2002); von Bueltzingsloewen, A., et al., Bone Marrow Transplant 12:197-202 (1993); Winston, D. J., et al., Ann. Intern. Med. 118:179-184 (1993); Goodrich, J. M., et al., Ann. Intern. Med. 118:173-178 (1993); Boeckh, M., et al., Blood 88:4063-4071 (1996); Salzberger, B., et al., Blood 90:2502-2508 (1997); Preiser, W., et al., J. Clin. Virol. 20:59-70 (2001); Grangeot-Keros, L., and Cointe, D., J. Clin. Virol. 21:213-221 (2001); Boeckh, M., and Bowden, R., Cancer Treat. Res. 76:97-136 (1995); Zaia, J. A., et al., Hematology (Am. Soc. Hematol. Educ. Program) 339-355 (2000)).

In addition to developing more rapid and sensitive diagnostics, molecular biological methods enable the development of defined subunit vaccines for human pathogens. Indeed, safe, effective recombinant subunit vaccines would significantly reduce, and perhaps eliminate, the need for therapeutic treatments. In the case of HCMV, control of infection has been correlated with antibody and T cell recognition of at least three viral proteins: pp65, glycoprotein B (gB), and the immediate early-1 protein (IE1).

The 65kD viral protein pp65, also known as ppUL83, lower matrix protein, ICP27, PK68, and pp64, is one of the most abundantly expressed structural proteins (FIG. 1). It is encoded by the UL83 gene of the viral genome (nucleotides 119352-121037 of the HCMV strain AD169 genomic sequence, Genbank X17403). This protein is believed to be processed for MHC presentation shortly after viral entry into cells, which allows it to be presented before other viral proteins shut down the antigen processing pathway in infected cells. Therefore, T cell recognition of this protein is important for infection control (Solache, et al. J. Immunol. 163:5512-5518 (1999)), which is herein incorporated by reference in its entirety.

Glycoprotein B (gB) is a 906 amino acid envelope glycoprotein (FIG. 4) encoded by UL55, nucleotides 80772-83495 of Genbank X17403). It is a type I integral membrane protein that participates in the fusion of the virion envelope with the cell membrane, is required for infectivity, is highly immunogenic, and has a high degree of conservation among HCMV strains, making this protein an attractive target for vaccines. The full-length protein contains an amino-terminal signal peptide (amino acids 1-24), an extracellular domain (amino acids 25-713), a putative trans-membrane anchor domain (amino acids 714-771) and an intracellular domain (amino acids 772-906). Deletion of the transmembrane anchor domain results in secretion of gB (Zheng et al. J. Virol. 70:8029-8040 (1996)). Additionally, the full-length protein is cleaved by host furin proteases between amino acids 460 and 461 to form the gp93 and gp55 cleavage products that remain tightly associated as a heterodimer. (Mocarski E. S. and C. T. Courcelle, pp. 2629-2674, Field's Virology, 4th ed., Eds. Knipe D M and Howley P M, Lippincott Williams & Wilkins, Philadelphia (2001)). Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

IE1 is a 491 amino acid protein (FIG. 7) encoded by HCMV ORF UL123 (Genbank X17403, nucleotides 171006-172765). The gene encodes a 1.9 Kb mRNA comprising four exons, with only exons 2-4 being translated. The 85 N-terminal amino acids are encoded by exons 2 and 3, with the remainder encoded by exon 4. IE2 is a related family of proteins that share exons 1-3 and an exon 5, with many splice variations. Together, IE1 and IE2 transactivate the HCMV major immediate early promoter to regulate viral transcription (Malone, C L. et al. J. Virol. 64:1498-1506 (1990); Mocarski, E. Fields Virology Ed. Field et al., 3^(rd) ed., pp. 2447-2491, Lippincott-Raven Publishers, Philadelphia (1996); Chee M. S. et al., Curr Topics Microbiol. Immunol. 154:125-169 (1990)). Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

IE1 has a kinase activity that is dependent on an ATP binding site encoded by amino acids 173-196. IE1 can autophosphorylate or phosphorylate cellular factors to transactivate E2F dependent transcription. Both exons 3 and 4 are required for viral transactivation, with the required regions in exon 4 being broadly distributed throughout the exon. The portion of the protein encoded by exon 4 is known to have a high degree of secondary structure. Although IE1 is transported to the nucleus, no nuclear localization signal has been identified. (Pajovic, S. et al. Mol. Cell. Bio. 17:6459-6464 (1997)). Gyulai et al. showed high levels of CTL response in vitro to effector cells expressing a nucleotide fragment consisting of exon 4 (Gyulai et al. J. Infectious Diseases 181:1537-1546 (2000)). Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

No vaccine is currently available for HCMV. However, clinical trials have been performed with live-attenuated HCMV vaccines, a canarypox-based vaccine, and a recombinant gB vaccine (Plotkin, S. A., Pediatr. Infect. Dis. J. 18:313-325 (1999)). The first HCMV vaccine tested in humans was a live attenuated virus vaccine made from the AD169 laboratory-adapted strain (Elek, S. D. and Stern, H., Lancet 1:1-5 (1974)). Local reactions were common, but HCMV was not isolated from any of the vaccine recipients. This vaccine was not investigated beyond initial Phase I studies.

Immune responses to HCMV have been determined by the study of acute and chronic HCMV infections in both animal models and in man. Antibody appears critical in the prevention of maternal-fetal transmission, and is primarily directed to the envelope glycoproteins, especially gB (Plotkin, S. A., Pediatr. Infect. Dis. J. 18:313-325 (1999); Fowler, K. B., N. Engl. J. Med. 326:663-667 (1992)).

In contrast, the control of HCMV infection in transplant recipients and HIV-infected persons is associated with preserved cellular immune responses, including CD4+, CD8+, and NK T cells. The CD8+ T-cell responses are directed primarily at the immediate early (IE) protein of HCMV and at the abundant tegument protein pp65 (Gyulai, Z., et al., J. Infect. Dis. 181:1537-1546 (2000); Tabi, Z., et al., J. Immunol. 166:5695-5703 (2001); Wills, M. R., et al., J. Virol. 70:7569-7579 (1996); Frankenberg, N., et al., Virology 295:208-216 (2002); Retiere, C., et al., J. Virol. 74:3948-3952 (2000); Koszinowski, U. H., et al., J. Virol. 61:2054-2058 (1987); Kern, F., et al., J. Infect. Dis. 185:1709-1716 (2002)). Approximately 92% of persons have CD8+ responses to pp65 and another 76% to exon 4 of IE1 (Gyulai, Z., et al., J. Infect. Dis. 181:1537-1546 (2000); Kern, F., et al., J. Infect. Dis. 185:1709-1716 (2002)). In addition, another one third of infected individuals have CTL responses to gB. Almost all infected persons have CD4+ responses to HCMV, although the gene and epitope mapping of these responses is not as fully investigated as those for CD8+ T cells (Kern, F., et al., J. Infect. Dis. 185:1709-1716 (2002); Davignon, J. L., et al., J. Virol. 70:2162-2169 (1996); He, H., et al., J. Gen. Virol. 76:1603-1610 (1995); Beninga, J., et al., J. Gen. Virol. 76:153-160 (1995). The helper T-cell responses in infected, healthy persons are sufficiently robust that HCMV is frequently used as a positive control in the development of methods for the measurement of CD4+ T-cell responses (Kern, F., et al., J. Infect. Dis. 185:1709-1716 (2002); Currier, J. R., et al., J. Immunol. Methods 260:157-172 (2002); Picker, L. J., et al., Blood 86:1408-1419 (1995)).

Other attempts to develop vaccines for HCMV have focused on administering purified or recombinant viral polypeptides, either full-length, modified, or short epitopes, to induce immune responses. In a review published by the American Society for Hematology, Zaia et al. describes various peptide-based approaches to developing HCMV vaccines, including using DNA vaccines to express wild-type and mutated proteins (Zaia, J. A. et al. Hematology 2000, Am Soc Hematol Educ Program, pp. 339-355, Am. Soc. Hematol. (2000)). Endresz et al. describes eliciting HCMV-specific CTL in mice immunized with plasmids encoding HCMV Towne strain full-length gB, expressed constitutively or under a tetracycline-regulatable promoter, and pp65 or a gB with the deletion of amino acids 715-772 (Endresv, V. et al. Vaccine 17:50-8 (1999); Endresz, V. et al. Vaccine 19:3972-80 (2001)). U.S. Pat. No. 6,100,064 describes a method of producing secreted gB polypeptides lacking the transmembrane domain but retaining the C terminal domain. U.S. Pat. Nos. 5,547,834 and 5,834,307 describe a gB polypeptide with amino acid substitutions at the endoproteolytic cleavage site to prevent proteolytic processing. U.S. Pat. Nos. 6,251,399 and 6,156,317 describe vaccines using short peptide fragments of pp65 comprising immunogenic epitopes. A number of other groups have analyzed epitopes in HCMV pp65 and gB for eliciting a strong immune response (Liu, Y N. et al. J. Gen. Virol. 74:2207-14 (1993); Ohlin, M. et al. J. Virol. 67:703-10 (1993); Navarro, D. et al. J. Med. Virol. 52:451-9 (1997); Khattab B A. et al. J. Med. Virol. 52:68-76 (1997); Diamond, D J. et al. Blood 90:1751067 (1997); Solache, A. et al. J. Immunol. 163:5512-8 (1999). U.S. Pat. No. 6,162,620 is directed to a polynucleotide encoding a wild-type gB or a gB lacking the membrane sequences. U.S. Pat. No. 6,133,433 is directed to a nucleotide encoding a full-length, wild-type pp65 or a specific 721 nt fragment thereof. Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

During the past few years there has been substantial interest in testing DNA-based vaccines for a number of infectious diseases where the need for a vaccine, or an improved vaccine, exists. Several well-recognized advantages of DNA-based vaccines include the speed, ease and cost of manufacture, the versatility of developing and testing multivalent vaccines, the finding that DNA vaccines can produce a robust cellular response in a wide variety of animal models as well as in man, and the proven safety of using plasmid DNA as a delivery vector (Donnelly, J. J., et al., Annu. Rev. Immunol. 15:617-648 (1997); Manickan, E., et al., Crit. Rev. Immunol. 17(2):139-154 (1997)). DNA vaccines represent the next generation in the development of vaccines (Nossal, G., Nat. Med. 4:475-476 (1998)) and numerous DNA vaccines are in clinical trials. Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

The immunotherapeutic product design is based on the concept of immunization by direct gene transfer. Plasmid-based immunotherapeutics offer the positive attributes of immune stimulation inherent to live-attenuated vaccines combined with the safety of recombinant subunit vaccines in an adjuvant formulation.

In the transplant population, control of HCMV disease is associated with a cellular immune response (Riddell, S. R., “Pathogenesis of cytomegalovirus pneumonia in immunocompromised hosts,” Semin. Respir. Infect. 10:199-208 (1995)) and thus an effective product should induce CD4+ and CD8+ T-cell responses. Formulated plasmid has been shown to induce such cellular immune responses, and does not have the safety concerns associated with the use of live vectors in the transplant setting (Shiver, J. W., et al., Nature 415:331-335 (2002)).

Retooling coding regions encoding polypeptides from pathogens using codon frequencies preferred in a given mammalian species often results in a significant increase in expression in the cells of that mammalian species, and concomitant increase in immunogenicity. See, e.g., Deml, L., et al., J. Virol. 75:10991-11001 (2001), and Narum, D L, et al., Infect. Immun. 69:7250-7253 (2001), all of which are herein incorporated by reference in its entirety.

There remains a need in the art for convenient, safe, and efficacious immunogenic compounds to protect humans against HCMV infection. The present invention provides safe yet effective immunogenic compounds and methods to protect humans, especially transplant recipients and immunocompromised individuals, against HCMV infection using such immunogenic compounds.

SUMMARY OF THE INVENTION

The present invention is directed to enhancing immune response of a human in need of protection against HCMV infection by administering in vivo, into a tissue of the human, a polynucleotide comprising a codon-optimized coding region encoding an HCMV polypeptide or a nucleic acid fragment of such a coding region encoding a fragment, a variant, or a derivative thereof. Nucleic acid fragments of the present invention are altered from their native state in one or more of the following ways. First, a nucleic acid fragment which encodes an HCMV polypeptide may be part or all of a codon-optimized coding region, optimized according to codon usage in humans. In addition, a nucleic acid fragment which encodes an HCMV polypeptide may be a fragment which encodes only a portion of a full-length polypeptide, and/or may be mutated so as to, for example, remove from the encoded polypeptide adventitious protein motifs present in the encoded polypeptide or virulence factors associated with the encoded polypeptide. For example, the nucleic acid sequence could be mutated so as not to encode adventitious anchoring motifs that prevent secretion of the polypeptide. Upon delivery, the polynucleotide of the invention is incorporated into the cells of the human in vivo, and a prophylactically or therapeutically effective amount of an HCMV polypeptide or fragment thereof is produced in vivo.

The invention further provides immunogenic compositions comprising a polynucleotide which comprises one or more codon-optimized coding regions encoding polypeptides of HCMV or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof. Such compositions may include various transfection facilitating or immunity enhancing agents, such as poloxamers, cationic lipids, or adjuvants.

The present invention further provides plasmids and other polynucleotide constructs for delivery of nucleic acid coding sequences to a vertebrate which provide expression of HCMV polypeptides, or fragments, variants, or derivatives thereof. The present inventions further provides carriers, excipients, transfection-facilitating agents, immunogenicity-enhancing agents, e.g. adjuvants, or other agent or agents to enhance the transfection, expression, or efficacy of the administered gene and its gene product.

The invention further provides methods for enhancing the immune response of a human to HCMV infection by administering to the tissues of a human one or more polynucleotides comprising one or more codon-optimized coding regions encoding polypeptides of HCMV or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof. In certain embodiments, the invention further provides methods for enhancing the immune response of a human patient to HCMV infection by sequentially administering two or more different immunogenic compositions to the tissues of the vertebrate. Such methods comprise initially administering one or more polynucleotides comprising one or more codon-optimized coding regions encoding polypeptides of HCMV or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof, to prime immunity, and then administering subsequently a different vaccine composition, for example a recombinant viral vaccine, a protein subunit vaccine, or a recombinant or killed bacterial vaccine or vaccines to boost the anti-HCMV immune response in a human.

The invention further provides methods for enhancing the immune response of a human patient to HCMV by administering to the tissues of a human one or more polynucleotides comprising one or more codon-optimized coding regions encoding polypeptides of HCMV, and also HCMV polypeptides or fragments, variants or derivatives thereof; or one or more non-optimized polynucleotides encoding HCMV polypeptides, fragments, variants or derivatives thereof.

The combination of HCMV polypeptides or polynucleotides encoding HCMV polypeptides or fragments, variants or derivatives thereof, with the codon-optimized nucleic acid compositions provides for therapeutically beneficial effects at dose sparing concentrations. For example, immunological responses sufficient for a therapeutically beneficial effect may be attained by using less of a conventional-type vaccine when supplemented or enhanced with the appropriate amount of a codon-optimized nucleic acid.

Conventional-type vaccines, include vaccine compositions comprising either dead, inert or fragments of a virus or bacteria, or bacterial or viral proteins or protein fragments, injected into the patient to elicit action by the immune system. With regard to the present invention, conventional-type vaccines include compositions comprising immunogenic polypeptides or nucleotides encoding immunogenic polypeptides, fragments, variants, or derivatives thereof, and vectors comprising nucleotides encoding immunogenic polypeptides, fragments, variants, or derivatives thereof, that are not products of, or do not contain codon-optimized polynucleotides as described herein. Thus, genetically engineered vaccines, are included in conventional-type vaccines, such as genetically engineered live vaccines, live chimeric vaccines, live replication-defective vaccines, subunit vaccines, peptide vaccines in various modifications of monovalent, multivalent, or chimeric subunit vaccines delivered as individual components or incorporated into virus-like particles for improved immunogenicity, and polynucleotide vaccines. Auxiliary agents, as described herein, are also considered components of conventional-type vaccines.

Thus, dose sparing is contemplated by administration of the combinatorial polynucleotide vaccine compositions of the present invention.

In particular, the dose of conventional-type vaccine may be reduced by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 70% when administered in combination, or prior to, or subsequent to, the codon-optimized nucleic acid compositions of the invention.

Similarly, a desirable level of an immunological response afforded by a DNA based pharmaceutical alone may be attained with less DNA by including a conventional-type DNA vaccine. Further, using a combination of a conventional-type vaccine and a codon-optimized DNA-based vaccine may allow both materials to be used in lesser amounts while still affording the desired level of immune response arising from administration of either component alone in higher amounts (e.g. one may use less of either immunological product when they are used in combination). This reduction in amounts of materials being delivered may be for each administration, in addition to reducing the number of administrations, in a vaccination regimen (e.g. 2 versus 3 or 4 injections). Further, the combination may also provide for reducing the kinetics of the immunological response (e.g. desired response levels are attained in 3 weeks instead of 6 after immunization).

In particular, the dose of a DNA based pharmaceutical, may be reduced by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 70% when administered in combination with conventional CMV vaccines.

Determining the precise amounts of DNA based pharmaceutical and conventional antigen is based on a number of factors as described herein, and is readily determined by one of ordinary skill in the art.

In addition to dose sparing, the claimed combinatorial compositions provide for a broadening of the immune response and/or enhanced beneficial immune responses. Such broadened or enhanced immune responses are achieved by: adding DNA to enhance cellular responses to a conventional-type vaccine; adding a conventional-type vaccine to a DNA pharmaceutical to enhanced humoral response; using a combination that induces additional epitopes (both humoral and/or cellular) to be recognized and/or more desirably responded to (epitope broadening); employing a DNA-conventional vaccine combination designed for a particular desired spectrum of immunological responses; obtaining a desirable spectrum by using higher amounts of either component. The broadened immune response is measurable by one of ordinary skill in the art by various standard immunological assays specific for the desirable response spectrum, which are described in more detail herein.

Both broadening and dose sparing may be obtained simultaneously.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows the wild-type nucleotide sequence (SEQ ID NO:1) and amino acid translation (SEQ ID NO:2) of full-length, native HCMV pp65 (Genbank WMBE65) from HCMV strain AD 169.

FIG. 2 shows a fully codon-optimized nucleotide sequence (SEQ ID NO:3) and amino acid translation (SEQ ID NO:4) of native HCMV pp65. The putative kinase site at amino acids Arg435-Lys438 is underlined.

FIGS. 3A-3E show the alignment of wild-type (“wt”) (SEQ ID NO:1) and fully codon-optimized (“opt”) (SEQ ID NO:9) nucleotide sequences encoding native HCMV pp65.

FIGS. 4A-4E show the wild-type nucleotide sequence (SEQ ID NO:11) and amino acid translation (SEQ ID NO:12) of HCMV gB strain AD169. SEQ ID NO:11 contains a nucleic acid fragment encoding the open reading frame for full-length HCMV gB (nucleotides 157-3125 of Genbank X04606). The host proteolytic cleavage site between amino acids 460 and 461 is marked by a colon.

FIGS. 5A-5D show a minimally codon-optimized nucleotide sequence (SEQ ID NO:13) and amino acid sequence (SEQ ID NO:14) of a truncated, secreted HCMV gB. SEQ ID NO:13 contains a nucleic acid encoding a minimal human codon-optimized secreted gB (SEQ ID NO:14).

FIGS. 6A-6G show the alignment of wild-type (“wt”) (SEQ ID NO:11) and fully codon-optimized (“opt”) (SEQ ID NO:16) nucleotide sequences encoding full-length wild-type HCMV gB.

FIGS. 7A-7B show the wild-type IE1 nucleotide sequence (SEQ ID NO:19), and amino acid translation (SEQ ID NO:20) of full-length, native IE1.

FIG. 8 shows the protocol for the preparation of a formulation comprising 0.3 mM BAK, 7.5 mg/ml CRL 1005, and 5 mg/ml of DNA in a final volume of 3.6 ml, through the use of thermal cycling.

FIG. 9 shows the protocol for the preparation of a formulation comprising 0.3 mM BAK, 34 mg/ml or 50 mg/ml CRL 1005, and 2.5 mg/ml DNA in a final volume of 4.0 ml, through the use of thermal cycling.

FIG. 10 shows the protocol for the simplified preparation (without thermal cycling) of a formulation comprising 0.3 mM BAK, 7.5 mg/ml CRL 1005, and 5 mg/ml DNA.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to compositions and methods for enhancing the immune response of a human in need of protection against HCMV infection by administering in vivo, into a tissue of a human, a polynucleotide comprising a human codon-optimized coding region encoding a polypeptide of HCMV, or a nucleic acid fragment of such a coding region encoding a fragment, variant, or derivative thereof. The polynucleotides are incorporated into the cells of the human in vivo, and an immunologically effective amount of the HCMV polypeptide, or fragment or variant is produced in vivo.

The present invention provides polynucleotide-based vaccines and methods for delivery of HCMV coding sequences to a human with optimal expression and safety conferred through codon optimization and/or other manipulations. These polynucleotide-based vaccines are prepared and administered in such a manner that the encoded gene products are optimally expressed in humans. As a result, these compositions and methods are useful in stimulating an immune response against HCMV infection. Also included in the invention are expression systems, delivery systems, and codon-optimized HCMV coding regions.

A polynucleotide vaccine of the present invention is capable of eliciting an immune response in a human against HCMV when administered to that human. Such polynucleotides are referred to herein as polynucleotide vaccines.

It is to be noted that the term “a” or “an” entity refers to one or more of that entity; for example, “a polynucleotide,” is understood to represent one or more polynucleotides. As such, the terms “a” (or “an”), “one or more,” and “at least one” can be used interchangeably herein.

The terms “nucleic acid” or “nucleic acid fragment” refers to any one or more nucleic acid segments, e.g., DNA or RNA fragments, present in a polynucleotide or construct. While the terms “nucleic acid,” as used herein, is meant to include any nucleic acid, the term “nucleic acid fragment” is used herein to specifically denote a fragment of a designed or synthetic codon-optimized coding region encoding a polypeptide, or fragment, variant, or derivative thereof, which has been optimized according to the codon usage of a given species. As used herein, a “coding region” is a portion of nucleic acid which consists of codons translated into amino acids. Although a “stop codon” (TAG, TGA, or TAA) is not translated into an amino acid, it may be considered to be part of a coding region, but any flanking sequences, for example promoters, ribosome binding sites, transcriptional terminators, and the like, are not part of a coding region. Two or more nucleic′ acids or nucleic acid fragments of the present invention can be present in a single polynucleotide construct, e.g., on a single plasmid, or in separate polynucleotide constructs, e.g., on separate plasmids. Furthermore, any nucleic acid or nucleic acid fragment may encode a single polypeptide, e.g., a single antigen, cytokine, or regulatory polypeptide, or may encode more than one polypeptide, e.g., a nucleic acid may encode two or more polypeptides. In addition, a nucleic acid may encode a regulatory element such as a promoter or a transcription terminator, or may encode heterologous coding regions, e.g. specialized elements or motifs, such as a secretory signal peptide or a functional domain.

The terms “fragment,” “variant,” “derivative” and “analog” when referring to HCMV polypeptides of the present invention include any polypeptides which retain at least some of the immunogenicity or antigenicity of the corresponding native polypeptide. Fragments of HCMV polypeptides of the present invention include proteolytic fragments, deletion fragments and in particular, fragments of HCMV polypeptides which exhibit increased secretion from the cell or higher immunogenicity when delivered to an animal. Polypeptide fragments further include any portion of the polypeptide which comprises an antigenic or immunogenic epitope of the native polypeptide, including linear as well as three-dimensional epitopes. Variants of HCMV polypeptides of the present invention includes fragments as described above, and also polypeptides with altered amino acid sequences due to amino acid substitutions, deletions, or insertions. Variants may occur naturally, such as an allelic variant. By an “allelic variant” is intended alternate forms of a gene occupying a given locus on a chromosome or genome of an organism or virus. Genes II, Lewin, B., ed., John Wiley & Sons, New York (1985), which is incorporated herein by reference. For example, as used herein, variations in a given gene product, e.g., pp65, between HCMV strains, e.g. Towne and AD169, would be considered “allelic variants.” Non-naturally occurring variants may be produced using art-known mutagenesis techniques. Variant polypeptides may comprise conservative or non-conservative amino acid substitutions, deletions or additions. Derivatives of HCMV polypeptides of the present invention, are polypeptides which have been altered so as to exhibit additional features not found on the native polypeptide. Examples include fusion proteins. An analog is another form of an HCMV polypeptide of the present invention. An example is a proprotein which can be activated by cleavage of the proprotein to produce an active mature polypeptide.

The term “polynucleotide” is intended to encompass a singular nucleic acid or nucleic acid fragment as well as plural nucleic acids or nucleic acid fragments, and refers to an isolated molecule or construct, e.g., a virus genome (e.g., a non-infectious viral genome), messenger RNA (mRNA), plasmid DNA (pDNA), or derivatives of pDNA (e.g., minicircles as described in (Darquet, A-M et al., Gene Therapy 4:1341-1349 (1997)) comprising a polynucleotide. A nucleic acid may be provided in linear (e.g., mRNA), circular (e.g., plasmid), or branched form as well as double-stranded or single-stranded forms. A polynucleotide may comprise a conventional phosphodiester bond or a non-conventional bond (e.g., an amide bond, such as found in peptide nucleic acids (PNA)).

The terms “infectious polynucleotide” or “infectious nucleic acid” are intended to encompass isolated viral polynucleotides and/or nucleic acids which are solely sufficient to mediate the synthesis of complete infectious virus particles upon uptake by permissive cells. “Isolated” means that the viral nucleic acid does not require pre-synthesized copies of any of the polypeptides it encodes, e.g., viral replicases, in order to initiate its replication cycle.

The terms “non-infectious polynucleotide” or “non-infectious nucleic acid” as defined herein are polynucleotides or nucleic acids which cannot, without additional added materials, e.g., polypeptides, mediate the synthesis of complete infectious virus particles upon uptake by permissive cells. An infectious polynucleotide or nucleic acid is not made “non-infectious” simply because it is taken up by a non-permissive cell. For example, an infectious viral polynucleotide from a virus with limited host range is infectious if it is capable of mediating the synthesis of complete infectious virus particles when taken up by cells derived from a permissive host (i.e., a host permissive for the virus itself). The fact that uptake by cells derived from a non-permissive host does not result in the synthesis of complete infectious virus particles does not make the nucleic acid “non-infectious.” In other words, the term is not qualified by the nature of the host cell, the tissue type, or the species.

In some cases, an isolated infectious polynucleotide or nucleic acid may produce fully-infectious virus particles in a host cell population which lacks receptors for the virus particles, i.e., is non-permissive for virus entry. Thus viruses produced will not infect surrounding cells. However, if the supernatant containing the virus particles is transferred to cells which are permissive for the virus, infection will take place.

The terms “replicating polynucleotide” or “replicating nucleic acid” are meant to encompass those polynucleotides and/or nucleic acids which, upon being taken up by a permissive host cell, are capable of producing multiple, e.g., one or more copies of the same polynucleotide or nucleic acid. Infectious polynucleotides and nucleic acids are a subset of replicating polynucleotides and nucleic acids; the terms are not synonymous. For example, a defective virus genome lacking the genes for virus coat proteins may replicate, e.g., produce multiple copies of itself, but is NOT infectious because it is incapable of mediating the synthesis of complete infectious virus particles unless the coat proteins, or another nucleic acid encoding the coat proteins, are exogenously provided.

In certain embodiments, the polynucleotide, nucleic acid, or nucleic acid fragment is DNA. In the case of DNA, a polynucleotide comprising a nucleic acid which encodes a polypeptide normally also comprises a promoter operably associated with the polypeptide-encoding nucleic acid. An operable association is when a nucleic acid encoding a gene product, e.g., a polypeptide, is associated with one or more regulatory sequences in such a way as to place expression of the gene product under the influence or control of the regulatory sequence(s). Two DNA fragments (such as a polypeptide-encoding nucleic acid and a promoter associated with the 5′ end of the nucleic acid) are “operably associated” if induction of promoter function results in the transcription of mRNA encoding the desired gene product and if the nature of the linkage between the two DNA fragments does not (1) result in the introduction of a frame-shift mutation, (2) interfere with the ability of the expression regulatory sequences to direct the expression of the gene product, or (3) interfere with the ability of the DNA template to be transcribed. Thus, a promoter region would be operably associated with a nucleic acid encoding a polypeptide if the promoter was capable of effecting transcription of that nucleic acid. The promoter may be a cell-specific promoter that directs substantial transcription of the DNA only in predetermined cells. Other transcription control elements, besides a promoter, for example enhancers, operators, repressors, and transcription termination signals, can be operably associated with the polynucleotide to direct cell-specific transcription. Suitable promoters and other transcription control regions are disclosed herein.

A variety of transcription control regions are known to those skilled in the art. These include, without limitation, transcription control regions which function in vertebrate cells, such as, but not limited to, promoter and enhancer segments from cytomegaloviruses (the immediate early promoter, in conjunction with intron-A), simian virus 40 (the early promoter), retroviruses (such as Rous sarcoma virus), and picornaviruses (particularly an internal ribosome entry site, or IRES, also referred to as a CITE sequence). Other transcription control regions include those derived from vertebrate genes such as actin, heat shock protein, bovine growth hormone and rabbit β-globin, as well as other sequences capable of controlling gene expression in eukaryotic cells. Additional suitable transcription control regions include tissue-specific promoters and enhancers as well as lymphokine-inducible promoters (e.g., promoters inducible by interferons or interleukins).

In one embodiment, a DNA polynucleotide of the present invention is a circular or linearized plasmid, or other linear DNA which is, in certain embodiments, non-infectious and nonintegrating (i.e., does not integrate into the genome of vertebrate cells). A linearized plasmid is a plasmid that was previously circular but has been linearized, for example, by digestion with a restriction endonuclease.

Alternatively, DNA virus genomes may be used to administer DNA polynucleotides into vertebrate cells. In certain embodiments, a DNA virus genome of the present invention is noninfectious, and nonintegrating. Suitable DNA virus genomes include herpesvirus genomes, adenovirus genomes, adeno-associated virus genomes, and poxvirus genomes. References citing methods for the in vivo introduction of non-infectious virus genomes to vertebrate tissues are well known to those of ordinary skill in the art, and are cited supra.

In other embodiments, a polynucleotide of the present invention is RNA. In a suitable embodiment, the RNA is in the form of messenger RNA (mRNA). Methods for introducing RNA sequences into vertebrate cells are described in U.S. Pat. No. 5,580,859, the disclosure of which is incorporated herein by reference in its entirety.

Polynucleotide, nucleic acids, and nucleic acid fragments of the present invention may be associated with additional nucleic acids which encode secretory or signal peptides, which direct the secretion of a polypeptide encoded by a nucleic acid or polynucleotide of the present invention. According to the signal hypothesis, proteins secreted by mammalian cells have a signal peptide or secretory leader sequence which is cleaved from the mature protein once export of the growing protein chain across the rough endoplasmic reticulum has been initiated. Those of ordinary skill in the art are aware that polypeptides secreted by vertebrate cells generally have a signal peptide fused to the N-terminus of the polypeptide, which is cleaved from the complete or “full-length” polypeptide to produce a secreted or “mature” form of the polypeptide. In certain embodiments, the native leader sequence is used, or a functional derivative of that sequence that retains the ability to direct the secretion of the polypeptide that is operably associated with it. Alternatively, a heterologous mammalian leader sequence, or a functional derivative thereof, may be used. For example, the wild-type leader sequence may be substituted with the leader sequence of human tissue plasminogen activator (TPA) or mouse β-glucuronidase.

In accordance with one aspect of the present invention, there is provided a plasmid for expression of an HCMV gB-derived or pp65-derived coding sequence optimized for expression in human cells, to be delivered to a human to be treated or immunized. Additional HCMV-derived coding sequences, e.g. coding for IE1, may also be included on the plasmid, or on a separate plasmid, and expressed, either using native codons or codons optimized for expression in humans to be treated or immunized. When such a plasmid encoding one or more optimized HCMV sequences is delivered, in vivo to a tissue of the human to be treated or immunized, the transcriptional unit will thus express the one or more encoded gene product(s). The level of expression of the gene product(s) will depend to a significant extent on the strength of the associated promoter and the presence and activation of an associated enhancer element, as well as the optimization of the coding region.

As used herein, the term “plasmid” refers to a construct made up of genetic material (i.e., nucleic acids). Typically a plasmid contains an origin of replication which is functional in bacterial host cells, e.g., Eschericha coli, and selectable markers for detecting bacterial host cells comprising the plasmid. Plasmids of the present invention may include genetic elements as described herein arranged such that an inserted coding sequence can be transcribed and translated in eukaryotic cells. Also, while the plasmid may include a sequence from a viral nucleic acid, such viral sequence normally does not cause the incorporation of the plasmid into a viral particle, and the plasmid is therefore a non-viral vector. In certain embodiments described herein, a plasmid is a closed circular DNA molecule.

The term “expression” refers to the biological production of a product encoded by a coding sequence. In most cases a DNA sequence, including the coding sequence, is transcribed to form a messenger-RNA (mRNA). The messenger-RNA is translated to form a polypeptide product which has a relevant biological activity. Also, the process of expression may involve further processing steps to the RNA product of transcription, such as splicing to remove introns, and/or post-translational processing of a polypeptide product.

As used herein, the term “polypeptide” is intended to encompass a singular “polypeptide” as well as plural “polypeptides,” and comprises any chain or chains of two or more amino acids. Thus, as used herein, terms including, but not limited to “peptide,” “dipeptide,” “tripeptide,” “protein,” “amino acid chain,” or any other term used to refer to a chain or chains of two or more amino acids, are included in the definition of a “polypeptide,” and the term “polypeptide” may be used instead of, or interchangeably with any of these terms. The term further includes polypeptides which have undergone post-translational modifications, for example, glycosylation, acetylation, phosphorylation, amidation, derivatization by known protecting/blocking groups, proteolytic cleavage, or modification by non-naturally occurring amino acids.

Also included as polypeptides of the present invention are fragments, derivatives, analogs, or variants of the foregoing polypeptides, and any combination thereof. Polypeptides, and fragments, derivatives, analogs, or variants thereof of the present invention can be antigenic and immunogenic polypeptides related to HCMV polypeptides, which are used to prevent or treat, i.e., cure, ameliorate, lessen the severity of, or prevent or reduce contagion of infectious disease caused by HCMV.

As used herein, an antigenic polypeptide or an immunogenic polypeptide is a polypeptide which, when introduced into a human, reacts with the human's immune system molecules, i.e., is antigenic, and/or induces an immune response in the human, i.e., is immunogenic. It is quite likely that an immunogenic polypeptide will also be antigenic, but an antigenic polypeptide, because of its size or conformation, may not necessarily be immunogenic. Examples of antigenic and immunogenic polypeptides of the present invention include, but are not limited to, HCMV pp65 or fragments or variants thereof, e.g. pp65-delArg435-Lys468; gB, or fragments thereof, e.g. consisting of amino acids 1-713, or variants thereof; and IE1 or fragments or variants thereof, e.g. ex4-IE1-delATP and derivatives thereof, e.g., any of the foregoing polypeptides fused to a TPA signal peptide.

The term “epitopes,” as used herein, refers to portions of a polypeptide having antigenic or immunogenic activity in an animal, for example a mammal, for example, a human. An “immunogenic epitope,” as used herein, is defined as a portion of a protein that elicits an immune response in an animal, as determined by any method known in the art. The term “antigenic epitope,” as used herein, is defined as a portion of a protein to which an antibody can immunospecifically bind its antigen as determined by any method well known in the art. Immunospecific binding excludes non-specific binding but does not necessarily exclude cross-reactivity with other antigens. Antigenic epitopes need not necessarily be immunogenic.

In the present invention, antigenic epitopes preferably contain a sequence of at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10, at least 15, at least 20, at least 25, or between about 15 to about 30 amino acids contained within the amino acid sequence of a polypeptide of the invention. Certain polypeptides comprising immunogenic or antigenic epitopes are at least 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, or 100 amino acid residues in length. Antigenic as well as immunogenic epitopes may be linear, i.e., be comprised of contiguous amino acids in a polypeptide, or may be three dimensional, i.e., where an epitope is comprised of non-contiguous amino acids which come together due to the secondary or tertiary structure of the polypeptide, thereby forming an epitope.

As to the selection of peptides or polypeptides bearing an antigenic epitope (e.g., that contain a region of a protein molecule to which an antibody or T cell receptor can bind), it is well known in that art that relatively short synthetic peptides that mimic part of a protein sequence are routinely capable of eliciting an antiserum that reacts with the partially mimicked protein. See, e.g., Sutcliffe, J. G., et al., Science 219:660-666 (1983).

Peptides capable of eliciting protein-reactive sera are frequently represented in the primary sequence of a protein, can be characterized by a set of simple chemical rules, and are confined neither to immunodominant regions of intact proteins (i.e., immunogenic epitopes) nor to the amino or carboxyl terminals. Peptides that are extremely hydrophobic and those of six or fewer residues generally are ineffective at inducing antibodies that bind to the mimicked protein; longer peptides, especially those containing proline residues, usually are effective. Sutcliffe et al., supra, at 661. For instance, 18 of 20 peptides designed according to these guidelines, containing 8-39 residues covering 75% of the sequence of the influenza virus hemagglutinin HA1 polypeptide chain, induced antibodies that reacted with the HA1 protein or intact virus; and 12/12 peptides from the MuLV polymerase and 18/18 from the rabies glycoprotein induced antibodies that precipitated the respective proteins. Non-limiting examples of antigenic polypeptides or peptides for HCMV pp65, gB and IE1 epitopes known to elicit cellular or humoral immune responses are listed in Table 1.

TABLE 1 Epitopes for immune recognition for HCMV proteins pp65, gB, and IE1. All of the references herein are incorporated by reference in its entirety. HCMV polypeptide Position Reference gB aa 178-194 Liu, YN. et al. J. Gen. Virol. 74: aa 190-204 2207-14 (1993) aa 250-264 aa 420-434 gB aa 67-86 Ohlin, M. et al. J. Virol. 67: 703-10 aa 549-635 (1993). aa 570-579 aa 606-619 gB aa 548-618 Navarro, D. et al. J. Med. Virol. 52: 451-9 (1997) pp65 aa 361-376 Khattab BA. et al. J. Med. Virol. aa 485-499 52: 68-76 (1997) pp65 aa 495-503 Diamond, DJ. et al. Blood 90: 1751067 (1997) pp65 aa 14-22 Solache, A. et al. J. Immunol. aa 120-128 163: 5512-8 aa 495-503 (1999) IE1 (UL123) aa 199-207 Khan, N. et al. J. Inf. Dis. 185: aa 279-287 000-000 (2002); aa 309-317 Elkington, R. et al. J. Virol. 77(9): aa 315-323 5226-5240 (2003). aa 378-389 aa 379-387 IE1 Class II aa 91-110 Davignon, J. et al. J. Virol. 70: aa 162-175 2162-2169 (1996); aa 96-115 Gautier, N. et al. Eur. J. Immunol. 26(5): 1110-7 (1996).

Antigenic epitope-bearing peptides and polypeptides of the invention are therefore useful to raise antibodies, including monoclonal antibodies, that bind specifically to a polypeptide of the invention. Thus, a high proportion of hybridomas obtained by fusion of spleen cells from donors immunized with an antigen epitope-bearing peptide generally secrete antibody reactive with the native protein. Sutcliffe et al., supra, at 663. The antibodies raised by antigenic epitope-bearing peptides or polypeptides are useful to detect the mimicked protein, and antibodies to different peptides may be used for tracking the fate of various regions of a protein precursor which undergoes post-translational processing. The peptides and anti-peptide antibodies may be used in a variety of qualitative or quantitative assays for the mimicked protein, for instance in competition assays since it has been shown that even short peptides (e.g. about 9 amino acids) can bind and displace the larger peptides in immunoprecipitation assays. See, for instance, Wilson, et al., Cell 37:767-778 (1984) at 777. The anti-peptide antibodies of the invention also are useful for purification of the mimicked protein, for instance, by adsorption chromatography using methods well known in the art.

In certain embodiments, the present invention is directed to polynucleotides comprising nucleic acids and fragments thereof comprising codon-optimized coding regions which encode polypeptides of HCMV, and in particular, HCMV gB or pp65, and fragments, variants, or derivatives thereof, alone or in combination with additional codon-optimized or non-codon-optimized HCMV-derived coding sequences, for example IE1 (SEQ ID NO:19).

“Codon optimization” is defined as modifying a nucleic acid sequence for enhanced expression in the cells of the vertebrate of interest, e.g. human, by replacing at least one, more than one, or a significant number, of codons of the native sequence with codons that are more frequently or most frequently used in the genes of that vertebrate. Various species exhibit particular bias for certain codons of a particular amino acid.

The present invention relates to polynucleotides comprising nucleic acid fragments of codon-optimized coding regions which encode HCMV polypeptides, or fragments, variants, or derivatives thereof, with the codon usage adapted for optimized expression in human cells. These polynucleotides are prepared by incorporating codons preferred for use in human genes into the DNA sequence. Also provided are polynucleotide expression constructs, vectors, and host cells comprising nucleic acid fragments of codon-optimized coding regions which encode HCMV polypeptides, and fragments, variants, or derivatives thereof, and various methods of using the polynucleotide expression constructs, vectors, host cells to treat or prevent HCMV disease in a human.

Polynucleotides comprising nucleic acid fragments of codon-optimized coding regions which encode polypeptides from nonhuman cytomegaloviruses, or fragments, variants, or derivatives thereof, may be optimized for expression in the cells of the vertebrate that can be infected by the nonhuman cytomegalovirus using the methods described herein. A partial list of known vertebrate cytomegaloviruses include murine CMV (MCMV), hamster CMV, guinea pig CMV, rat CMV, rabbit CMV, porcine CMV, bovine CMV, equine CMV, rhesus macaque CMV, African green monkey CMV, and chimpanzee CMV, as well as others (Staczek, J., Am. Soc. Microbiol. 545:247-265 (1990)). For example, an MCMV gene would be optimized for expressing in mouse cells, and an equine CMV gene would be optimized for expression in horse cells.

Codon Optimization

As used herein the term “codon-optimized coding region” means a nucleic acid coding region that has been adapted for expression in the cells of a given vertebrate by replacing at least one, or more than one, or a significant number, of codons with one or more codons that are more frequently used in the genes of that vertebrate.

Deviations in the nucleotide sequence that comprise the codons encoding the amino acids of any polypeptide chain allow for variations in the sequence coding for the gene. Since each codon consists of three nucleotides, and the nucleotides comprising DNA are restricted to four specific bases, there are 64 possible combinations of nucleotides, 61 of which encode amino acids (the remaining three codons encode signals ending translation). The “genetic code” which shows which codons encode which amino acids is reproduced herein as Table 2. As a result, many amino acids are designated by more than one codon. For example, the amino acids alanine and proline are coded for by four triplets, serine and arginine by six, whereas tryptophan and methionine are coded by just one triplet. This degeneracy allows for DNA base composition to vary over a wide range without altering the amino acid sequence of the proteins encoded by the DNA.

TABLE 2 The Standard Genetic Code T C A G T TTT Phe (F) TCT Ser (S) TAT Tyr (Y) TGT Cys (C) TTC Phe (F) TCC Ser (S) TAC Tyr (Y) TGC TTA Leu (L) TCA Ser (S) TAA Ter TGA Ter TTG Leu (L TCG Ser (S) TAG Ter TGG Trp (W) C CTT Leu (L) CCT Pro (P) CAT His (H) CGT Arg (R) CTC Leu (L) CCC Pro (P) CAC His (H) CGC Arg (R) CTA Leu (L) CCA Pro (P) CAA Gln (Q) CGA Arg (R) CTG Leu (L) CCG Pro (P) CAG Gln (Q) CGG Arg (R) A ATT Ile (I) ACT Thr (T) AAT Asn (N) AGT Ser (S) ATC Ile (I) ACC Thr (T) AAC Asn (N) AGC Ser (S) ATA Ile (I) ACA Thr (T) AAA Lys (K) AGA Arg (R) ATG Met (M) ACG Thr (T) AAG Lys (K) AGG Arg (R) G GTT Val (V) GCT Ala (A) GAT Asp (D) GGT Gly (G) GTC Val (V) GCC Ala (A) GAC Asp (D) GGC Gly (G) GTA Val (V) GCA Ala (A) GAA Glu (E) GGA Gly (G) GTG Val (V) GCG Ala (A) GAG Glu (E) GGG Gly (G)

Many organisms display a bias for use of particular codons to code for insertion of a particular amino acid in a growing peptide chain. Codon preference or codon bias, differences in codon usage between organisms, is afforded by degeneracy of the genetic code, and is well documented among many organisms. Codon bias often correlates with the efficiency of translation of messenger RNA (mRNA), which is in turn believed to be dependent on, inter alia, the properties of the codons being translated and the availability of particular transfer RNA (tRNA) molecules. The predominance of selected tRNAs in a cell is generally a reflection of the codons used most frequently in peptide synthesis. Accordingly, genes can be tailored for optimal gene expression in a given organism based on codon optimization.

Given the large number of gene sequences available for a wide variety of animal, plant and microbial species, it is possible to calculate the relative frequencies of codon usage. Codon usage tables are readily available, for example, at the “Codon Usage Database” available at www_kazusa_orjp/codon/ (visited Jul. 9, 2002), and these tables can be adapted in a number of ways. See Nakamura, Y., et al. “Codon usage tabulated from the international DNA sequence databases: status for the year 2000” Nucl. Acids Res. 28:292 (2000). The codon usage table for human, calculated from GenBank Release 128.0 [15 Feb. 2002], is reproduced below as Table 3. These tables use mRNA nomenclature, and so instead of thymine (T) which is found in DNA, the tables use uracil (U) which is found in RNA. The tables have been adapted so that frequencies are calculated for each amino acid, rather than for all 64 codons. For comparison, the codon usage table for human cytomegalovirus is reproduced below as Table 4.

TABLE 3 Codon Usage Table for Human Genes (Homo sapiens) Amino Acid Codon Number Frequency Phe UUU 326146 0.4525 Phe UUC 394680 0.5475 Total 720826 Leu UUA 139249 0.0728 Leu UUG 242151 0.1266 Leu CUU 246206 0.1287 Leu CUC 374262 0.1956 Leu CUA 133980 0.0700 Leu CUG 777077 0.4062 Total 1912925 Ile AUU 303721 0.3554 Ile AUC 414483 0.4850 Ile AUA 136399 0.1596 Total 854603 Met AUG 430946 1.0000 Total 430946 Val GUU 210423 0.1773 Val GUC 282445 0.2380 Val GUA 134991 0.1137 Val GUG 559044 0.4710 Total 1186903 Ser UCU 282407 0.1840 Ser UCC 336349 0.2191 Ser UCA 225963 0.1472 Ser UCG 86761 0.0565 Ser AGU 230047 0.1499 Ser AGC 373362 0.2433 Total 1534889 Pro CCU 333705 0.2834 Pro CCC 386462 0.3281 Pro CCA 322220 0.2736 Pro CCG 135317 0.1149 Total 1177704 Thr ACU 247913 0.2419 Thr ACC 371420 0.3624 Thr ACA 285655 0.2787 Thr ACG 120022 0.1171 Total 1025010 Ala GCU 360146 0.2637 Ala GCC 551452 0.4037 Ala GCA 308034 0.2255 Ala GCG 146233 0.1071 Total 1365865 Tyr UAU 232240 0.4347 Tyr UAC 301978 0.5653 Total 534218 His CAU 201389 0.4113 His CAC 288200 0.5887 Total 489589 Gln CAA 227742 0.2541 Gln CAG 668391 0.7459 Total 896133 Asn AAU 322271 0.4614 Asn AAC 376210 0.5386 Total 698481 Lys AAA 462660 0.4212 Lys AAG 635755 0.5788 Total 1098415 Asp GAU 430744 0.4613 Asp GAC 502940 0.5387 Total 933684 Glu GAA 561277 0.4161 Glu GAG 787712 0.5839 Total 1348989 Cys UGU 190962 0.4468 Cys UGC 236400 0.5532 Total 427362 Trp UGG 248083 1.0000 Total 248083 Arg CGU 90899 0.0830 Arg CGC 210931 0.1927 Arg CGA 122555 0.1120 Arg CGG 228970 0.2092 Arg AGA 221221 0.2021 Arg AGG 220119 0.2011 Total 1094695 Gly GGU 209450 0.1632 Gly GGC 441320 0.3438 Gly GGA 315726 0.2459 Gly GGG 317263 0.2471 Total 1283759 Stop UAA 13963 Stop UAG 10631 Stop UGA 24607

TABLE 4 Codon Usage Table for Human Cytomegalovirus (human herpesvirus 5) Amino Acid Codon Number Frequency Phe UUU 5435 0.5456 Phe UUC 4527 0.4544 Total 9962 Leu UUA 1191 0.0510 Leu UUG 3683 0.1578 Leu CUU 2162 0.0926 Leu CUC 5473 0.2344 Leu CUA 1771 0.0759 Leu CUG 9066 0.3883 Total 23346 Ile AUU 2452 0.2538 Ile AUC 6135 0.6350 Ile AUA 1075 0.1113 Total 9662 Met AUG 5051 1.0000 Total 430946 Val GUU 2271 0.1167 Val GUC 5082 0.2611 Val GUA 2570 0.1320 Val GUG 9541 0.4902 Total 19464 Ser UCU 2350 0.1234 Ser UCC 3911 0.2054 Ser UCA 1296 0.0681 Ser UCG 4876 0.2561 Ser AGU 1927 0.1012 Ser AGC 4677 0.2457 Total 19037 Pro CCU 1817 0.1439 Pro CCC 4425 0.3506 Pro CCA 1391 0.1102 Pro CCG 4990 0.3953 Total 12623 Thr ACU 2156 0.1368 Thr ACC 5648 0.3584 Thr ACA 1782 0.1131 Thr ACG 6173 0.3917 Total 15759 Ala GCU 2559 0.1491 Ala GCC 8013 0.4668 Ala GCA 1386 0.0807 Ala GCG 5209 0.3034 Total 17167 Tyr UAU 2321 0.2629 Tyr UAC 6509 0.7371 Total 8830 His CAU 1906 0.2753 His CAC 5018 0.7247 Total 6924 Gln CAA 2894 0.3398 Gln CAG 5623 0.6602 Total 8517 Asn AAU 2268 0.2892 Asn AAC 5574 0.7108 Total 7842 Lys AAA 3313 0.4408 Lys AAG 4203 0.5592 Total 7516 Asp GAU 3514 0.3023 Asp GAC 8110 0.6977 Total 11624 Glu GAA 4310 0.3684 Glu GAG 7390 0.6316 Total 11700 Cys UGU 3059 0.4265 Cys UGC 4113 0.5735 Total 7172 Trp UGG 2797 1.0000 Total 2797 Arg CGU 3747 0.2186 Arg CGC 6349 0.3703 Arg CGA 1826 0.1065 Arg CGG 3285 0.1916 Arg AGA 1185 0.0691 Arg AGG 752 0.0439 Total 17144 Gly GGU 3521 0.2430 Gly GGC 6952 0.4797 Gly GGA 1885 0.1301 Gly GGG 2133 0.1472 Total 14491 Stop UAA 310 Stop UAG 69 Stop UGA 234

By utilizing these or similar tables, one of ordinary skill in the art can apply the frequencies to any given polypeptide sequence, and produce a nucleic acid fragment of a codon-optimized coding region which encodes the polypeptide, but which uses codons more optimal for a given species. Codon-optimized coding regions can be designed by various different methods.

In one method, termed “uniform optimization,” a codon usage table is used to find the single most frequent codon used for any given amino acid, and that codon is used each time that particular amino acid appears in the polypeptide sequence. For example, referring to Table 3 above, for leucine, the most frequent codon is CUG, which is used 41% of the time. Thus all the leucine residues in a given amino acid sequence would be assigned the codon CUG. Human “uniform” codon-optimized nucleotide sequences encoding native pp65 from HCMV strain AD169 (SEQ ID NO:2)) (FIG. 1) and full-length gB from strain AD169 (SEQ ID NO:12) (FIG. 4) are presented herein as SEQ ID NO:7 and SEQ ID NO:15, respectively.

In another method, termed “full-optimization,” the actual frequencies of the codons are distributed randomly throughout the coding region. Thus, using this method for optimization, if a hypothetical polypeptide sequence had 100 leucine residues, referring to Table 3 for frequency of usage in the humans, about 7, or 7% of the leucine codons would be UUA, about 13, or 13% of the leucine codons would be UUG, about 13, or 13% of the leucine codons would be CUU, about 20, or 20% of the leucine codons would be CUC, about 7, or 7% of the leucine codons would be CUA, and about 41, or 41% of the leucine codons would be CUG. These frequencies would be distributed randomly throughout the leucine codons in the coding region encoding the hypothetical polypeptide. As will be understood by those of ordinary skill in the art, the distribution of codons in the sequence can vary significantly using this method, however, the sequence always encodes the same polypeptide. Three different human codon-optimized nucleotide sequences encoding native pp65 (SEQ ID NO:2) which have been optimized using this method are presented herein as SEQ ID NO:8, SEQ ID NO:9, and SEQ ID NO:10. Three different human codon-optimized sequences encoding native gB (SEQ ID NO:12) which have been fully optimized using this method are presented herein as SEQ ID NO:16, SEQ ID NO:17 and SEQ ID NO:18, respectively.

In using the “full-optimization” method, an entire polypeptide sequence, or fragment, variant, or derivative thereof is codon-optimized by any of the methods described herein. Various desired fragments, variants or derivatives are designed, and each is then codon-optimized individually. Alternatively, a full-length polypeptide sequence is codon-optimized for a given species resulting in a codon-optimized coding region encoding the entire polypeptide, and then nucleic acid fragments of the codon-optimized coding region, which encode fragments, variants, and derivatives of the polypeptide are made from the original codon-optimized coding region. As would be well understood by those of ordinary skill in the art, if codons have been randomly assigned to the full-length coding region based on their frequency of use in a given species, nucleic acid fragments encoding fragments, variants, and derivatives would not necessarily be fully codon-optimized for the given species. However, such sequences are still much closer to the codon usage of the desired species than the native codon usage. The advantage of this approach is that synthesizing codon-optimized nucleic acid fragments encoding each fragment, variant, and derivative of a given polypeptide, although routine, would be time consuming and would result in significant expense.

When using the “full-optimization” method, the term “about” is used precisely to account for fractional percentages of codon frequencies for a given amino acid. As used herein, “about” is defined as one amino acid more or one amino acid less than the value given. The whole number value of amino acids is rounded up if the fractional frequency of usage is 0.50 or greater, and is rounded down if the fractional frequency of use is 0.49 or less. Using again the example of the frequency of usage of leucine in human genes for a hypothetical polypeptide having 62 leucine residues, the fractional frequency of codon usage would be calculated by multiplying 62 by the frequencies for the various codons. Thus, 7.28 percent of 62 equals 4.51 UUA codons, or “about 5,” i.e., 4, 5, or 6 UUA codons, 12.66 percent of 62 equals 7.85 UUG codons or “about 8,” i.e., 7, 8, or 9 UUG codons, 12.87 percent of 62 equals 7.98 CUU codons, or “about 8,” i.e., 7, 8, or 9 CUU codons, 19.56 percent of 62 equals 12.13 CUC codons or “about 12,” i.e., 11, 12, or 13 CUC codons, 7.00 percent of 62 equals 4.34 CUA codons or “about 4,” i.e., 3, 4, or 5 CUA codons, and 40.62 percent of 62 equals 25.19 CUG codons, or “about 25,” i.e., 24, 25, or 26 CUG codons.

In a third method termed “minimal optimization,” coding regions are only partially optimized. For example, the invention includes a nucleic acid fragment of a codon-optimized coding region encoding a polypeptide in which at least about 1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 100% of the codon positions have been codon-optimized for a given species. That is, they contain a codon that is preferentially used in the genes of a desired species, e.g., a vertebrate species, e.g., humans, in place of a codon that is normally used in the native nucleic acid sequence. Codons that are rarely found in human genes are changed to codons more commonly utilized in human coding regions. To illustrate this method, a comparative chart showing codon usage per thousand of human and HCMV coding regions is presented in Table 5. The data is expressed as the number of times a given codon is used per 1000 codons. For instance, the asterisked codons in Table 5 for alanine, arginine, proline, serine, and threonine are frequently used in the genome of HCMV, but less frequently used in human genes. Starting with the native coding region of the HCMV gene of interest, one or more codons which are infrequently-used may be changed to more commonly-used human codons either by substituting one of the codons more frequently used in human genes. According to this method, these HCMV codons which are used at the same or higher frequency in human genes as compared to HCMV genes are left unchanged.

TABLE 5 Codon Usage Table for Human Genes and HCMV Amino Acid Codon Human hCMV Ala A GCA 16 6 * GCG 8 22 GCC 19 34 GCT 19 11 Arg R AGA 12 5 AGG 11 3 CGA 6 8 CGG 12 14 CGC 11 27 * CGT 5 16 Asn N AAC 20 24 AAT 17 10 Asp D GAC 26 34 GAT 22 15 Cys C TGC 12 17 TGT 10 13 Gln Q CAA 12 12 CAG 35 24 Glu E GAA 30 18 GAG 40 31 Gly G GGA 16 8 GGG 16 9 GGC 23 29 GGT 11 15 His H CAC 15 21 CAT 11 8 Ile I ATA 7 5 ATC 22 26 ATT 16 10 Leu L CTA 7 8 CTG 40 38 CTC 20 23 CTT 13 9 TTA 7 5 TTG 13 16 Lys K AAA 24 14 AAG 33 18 Met M ATG 22 21 Phe F TTC 21 19 TTT 17 23 Pro P CCA 17 6 * CCG 7 21 CCC 20 19 CCT 17 8 Ser S AGC 19 20 AGT 12 8 TCA 12 6 * TCG 5 21 TCC 18 17 TCT 15 10 Thr T ACA 15 8 * ACG 6 26 ACC 19 24 ACT 13 9 Trp W TGG 13 12 Tyr Y TAC 16 27 TAT 12 10 Val V GTA 7 11 GTG 29 40 GTC 15 21 GTT 11 10 Term TAA 1 1 TAG 0.5 0 TGA 1 1

Thus, those codons which are used more frequently in the HCMV genome than in human genes are substituted with the most frequently-used human codon. The difference in frequency at which the HCMV codons are substituted may vary based on a number factors as discussed below. For example, codons used at least twice more per thousand in HCMV genes as compared to human genes are substituted with the most frequently used human codon for that amino acid. This ratio may be adjusted higher or lower depending on various factors such as those discussed below. Accordingly, a codon in an HCMV native coding region would be substituted with the codon used most frequently for that amino acid in human coding regions if the codon is used 1.1 times, 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times, 1.7 times, 1.8 times, 1.9 times, 2.0 times, 2.1 times, 2.2 times, 2.3 times, 2.4 times, 2.5 times, 2.6 times, 2.7 times, 2.8 times, 2.9 times, 3.0 times, 3.1 times, 3.2 times, 3.3, times, 3.4 times, 3.5 times, 3.6 times, 3.7 times, 3.8 times, 3.9 times, 4.0 times, 4.1 times, 4.2 times, 4.3 times, 4.4 times, 4.5 times, 4.6 times, 4.7 times, 4.8 times, 4.9 times, 5.0 times, 5.5 times, 6.0 times, 6.5 times, 7.0 times, 7.5 times, 8.0 times, 8.5 times, 9.0 times, 9.5 times, 10.0 times, 10.5 times, 11.0 times, 11.5 times, 12.0 times, 12.5 times, 13.0 times, 13.5 times, 14.0 times, 14.5 times, 15.0 times, 15.5 times, 16.0 times, 16.5 times, 17.0 times, 17.5 times, 18.0 times, 18.5 times, 19.0 times, 19.5 times, 20 times, 21 times, 22 times, 23 times, 24 times, 25 times, or greater more frequently in HCMV coding regions than in human coding regions.

This minimal human codon optimization for highly variant codons has several advantages, which include but are not limited to the following examples. Since fewer changes are made to the nucleotide sequence of the gene of interest, fewer manipulations are required, which leads to reduced risk of introducing unwanted mutations and lower cost, as well as allowing the use of commercially available site-directed mutagenesis kits, reducing the need for expensive oligonucleotide synthesis. Further, decreasing the number of changes in the nucleotide sequence decreases the potential of altering the secondary structure of the sequence, which can have a significant impact on gene expression in certain host cells. The introduction of undesirable restriction sites is also reduced, facilitating the subcloning of the genes of interest into the plasmid expression vector.

Randomly assigning codons at an optimized frequency to encode a given polypeptide sequence, can be done manually by calculating codon frequencies for each amino acid, and then assigning the codons to the polypeptide sequence randomly. Additionally, various algorithms and computer software programs are readily available to those of ordinary skill in the art. For example, the “EditSeq” function in the Lasergene Package, available from DNAstar, Inc., Madison, Wis., the backtranslation function in the VectorNTl Suite, available from InforMax, Inc., Bethesda, Md., and the “backtranslate” function in the GCG—Wisconsin Package, available from Accelrys, Inc., San Diego, Calif. In addition, various resources are publicly available to codon-optimize coding region sequences. For example, the “backtranslation” function is proved on the world wide web by Entelechon GMBH at www_entelechon_com/eng/backtranslation_html (visited Jul. 9, 2002), “backtranseq” function available at bioinfo.pbi.nrc.ca:—8090/EMBOSS/index.html (visited Oct. 15, 2002). Constructing a rudimentary algorithm to assign codons based on a given frequency can also easily be accomplished with basic mathematical functions by one of ordinary skill in the art.

A number of options are available for synthesizing codon-optimized coding regions designed by any of the methods described above, using standard and routine molecular biological manipulations well known to those of ordinary skill in the art. In one approach, a series of complementary oligonucleotide pairs of 80-90 nucleotides each in length and spanning the length of the desired sequence are synthesized by standard methods. These oligonucleotide pairs are synthesized such that upon annealing, they form double stranded fragments of 80-90 base pairs, containing cohesive ends, e.g., each oligonucleotide in the pair is synthesized to extend 3, 4, 5, 6, 7, 8, 9, 10, or more bases beyond the region that is complementary to the other oligonucleotide in the pair. The single-stranded ends of each pair of oligonucleotides is designed to anneal with the single-stranded end of another pair of oligonucleotides. The oligonucleotide pairs are allowed to anneal, and approximately five to six of these double-stranded fragments are then allowed to anneal together via the cohesive single stranded ends, and then they ligated together and cloned into a standard bacterial cloning vector, for example, a TOPO® vector available from Invitrogen Corporation, Carlsbad, Calif. The construct is then sequenced by standard methods. Several of these constructs consisting of 5 to 6 fragments of 80 to 90 base pair fragments ligated together, i.e., fragments of about 500 base pairs, are prepared, such that the entire desired sequence is represented in a series of plasmid constructs. The inserts of these plasmids are then cut with appropriate restriction enzymes and ligated together to form the final construct. The final construct is then cloned into a standard bacterial cloning vector, and sequenced. Additional methods would be immediately apparent to the skilled artisan. In addition, gene synthesis is readily available commercially.

The codon-optimized coding regions can be versions encoding any gene products from any strain of HCMV, or fragments, variants, or derivatives of such gene products. Described herein are nucleic acid fragments of codon-optimized coding regions encoding the HCMV pp65 polypeptide and the HCMV glycoprotein B (gB) polypeptide, the nucleic acid fragments encoding the complete polypeptide, as well as various fragments, variants, and derivatives thereof, although other pp65 or gB-encoding nucleic acid sources are not excluded. Codon-optimized coding regions encoding other HCMV polypeptides (e.g. IE1), or fragments, variants and derivatives thereof, are included within the present invention. Additional, non-codon-optimized polynucleotides encoding HCMV polypeptides may be included as well.

The present invention is directed to compositions and methods of enhancing the immune response of a human in need of protection against HCMV infection by administering in vivo, into a tissue of a human, a polynucleotide comprising a codon-optimized coding region encoding a polypeptide of HCMV, or a nucleic acid fragment of such a coding region encoding a fragment, variant or derivative thereof. Human-codon optimization is carried out by the methods described herein, for example, in certain embodiments codon-optimized coding regions encoding polypeptides of HCMV, or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof are optimized according to human codon usage. The polynucleotides of the invention are incorporated into the cells of the human in vivo, and an immunologically effective amount of an HCMV polypeptide is produced in vivo.

In particular, the present invention relates to codon-optimized coding regions encoding polypeptides of HCMV, or nucleic acid fragments of such coding regions fragments, variants, or derivatives thereof which have been optimized according to human codon usage. For example, human codon-optimized coding regions encoding polypeptides of HCMV, or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof are prepared by substituting one or more codons preferred for use in human genes for the codons naturally used in the DNA sequence encoding the HCMV polypeptide. Also provided are polynucleotides, vectors, and other expression constructs comprising codon-optimized coding regions encoding polypeptides of HCMV, or nucleic acid fragments of such coding regions encoding fragments, variants, or derivatives thereof, and various methods of using such polynucleotides, vectors and other expression constructs. Coding regions encoding HCMV polypeptides may be uniformly optimized, fully optimized, or minimally optimized, as described herein.

The present invention is further directed towards polynucleotides comprising codon-optimized coding regions encoding polypeptides of HCMV antigens, for example, HCMV pp65, gB, and optionally in conjunction with other HCMV antigens, e.g. IE1. The invention is also directed to polynucleotides comprising codon-optimized nucleic acid fragments encoding fragments, variants and derivatives of these polypeptides.

The present invention provides isolated polynucleotides comprising codon-optimized coding regions of HCMV pp65, or fragments, variants, or derivatives thereof. In certain embodiments described herein, a codon-optimized coding region encoding SEQ ID NO:2 is optimized according to codon usage in humans (Homo sapiens).

Codon-optimized coding regions encoding SEQ ID NO:2, fully optimized according to codon usage in humans are designed as follows. The amino acid composition of SEQ ID NO:2 is shown in Table 6.

TABLE 6 Amino Acid Composition of Wild-Type HCMV pp65 from strain AD169 (SEQ ID NO: 2). Number in Amino Acid SEQ ID NO: 2 A Ala 38 R Arg 36 C Cys 10 G Gly 36 H His 24 I Ile 25 L Leu 41 K Lys 22 M Met 16 F Phe 19 P Pro 38 S Ser 41 T Thr 37 W Trp 9 Y Tyr 15 V Val 44 N Asn 18 D Asp 28 Q Gln 31 E Glu 33

Using the amino acid composition shown in Table 6, and the human codon usage table shown in Table 3, a human codon-optimized coding region which encodes SEQ ID NO:2 can be designed by any of the methods discussed herein.

In the “uniform optimization” approach, each amino acid is assigned the most frequent codon used in the human genome for that amino acid as indicated on Table 3. According to this method, codons are assigned to the coding region encoding SEQ ID NO:2 as follows: the 19 phenylalanine codons are TTC, the 41 leucine codons are CTG, the 25 isoleucine codons are ATC, the 16 methionine codons are ATG, the 44 valine codons are GTG, the 41 serine codons are AGC, the 38 proline codons are CCC, the 37 threonine codons are ACC, the 38 alanine codons are GCC, the 15 tyrosine codons are TAC, the 24 histidine codons are CAC, the 31 glutamine codons are CAG, the 18 asparagine codons are AAC, the 22 lysine codons are AAG, the 28 aspartic acid codons are GAC, the 33 glutamic acid codons are GAG, the 10 cysteine codons are TGC, the 9 tryptophan codons are TGG, the 36 arginine codons are CGG, AGA, or AGG (the frequencies of usage of these three codons in the human genome are not significantly different), and the 36 glycine codons are GGC. The codon-optimized pp65 coding region designed by this method is presented herein as SEQ ID NO:7.

Alternatively, a “fully codon-optimized” coding region which encodes SEQ ID NO:2 can be designed by randomly assigning each of any given amino acid a codon based on the frequency that codon is used in the human genome. These frequencies are shown in Table 3 above. Using this latter method, codons are assigned to the coding region encoding SEQ ID NO:2 as follows: about 9 of the 19 phenylalanine codons are TTT, and about 10 of the phenylalanine codons are TTC; about 3 of the 41 leucine codons are TTA, about 5 of the leucine codons are TTG, about 5 of the leucine codons are CTT, about 8 of the leucine codons are CTC, about 3 of the leucine codons are CTA, and about 17 of the leucine codons are CTG; about 9 of the 25 isoleucine codons are ATT, about 12 of the isoleucine codons are ATC, and about 4 of the isoleucine codons are ATA; the 16 methionine codons are ATG; about 8 of the 44 valine codons are GTT, about 10 of the valine codons are GTC, about 5 of the valine codons are GTA, and about 21 of the valine codons are GTG; about 8 of the 41 serine codons are TCT, about 9 of the serine codons are TCC, about 6 of the serine codons are TCA, about 2 of the serine codons are TCG, about 6 of the serine codons are AGT, and about 10 of the serine codons are AGC; about 11 of the 38 proline codons are CCT, about 12 of the proline codons are CCC, about 10 of the proline codons are CCA, and about 4 of the proline codons are CCG; about 9 of the 37 threonine codons are ACT, about 13 of the threonine codons are ACC, about 11 of the threonine codons are ACA, and about 4 of the threonine codons are ACG; about 10 of the 38 alanine codons are GCT, about 15 of the alanine codons are GCC, about 9 of the alanine codons are GCA, and about 4 of the alanine codons are GCG; about 7 of the 15 tyrosine codons are TAT and about 8 of the tyrosine codons are TAC; about 10 of the 24 histidine codons are CAT and about 14 of the histidine codons are CAC; about 8 of the 31 glutamine codons are CAA and about 23 of the glutamine codons are CAG; about 8 of the 18 asparagine codons are AAT and about 10 of the asparagine codons are AAC; about 9 of the 22 lysine codons are AAA and about 13 of the lysine codons are AAG; about 13 of the 28 aspartic acid codons are GAT and about 15 of the aspartic acid codons are GAC; about 14 of the 33 glutamic acid codons are GAA and about 19 of the glutamic acid codons are GAG; about 4 of the 10 cysteine codons are TGU and about 6 of the cysteine codons are TGC; the 9 tryptophan codons are TGG; about 3 of the 36 arginine codons are CGT, about 7 of the arginine codons are CGC, about 4 of the arginine codons are CGA, about 8 of the arginine codons are CGG, about 7 of the arginine codons are AGA, and about 7 of the arginine codons are AGG; and about 6 of the 36 glycine codons are GGT, about 12 of the glycine codons are GGC, about 9 of the glycine codons are GGA, and about 9 of the glycine codons are GGG.

As described above, the term “about” means that the number of amino acids encoded by a certain codon may be one more or one less than the number given. It would be understood by those of ordinary skill in the art that the total number of any amino acid in the polypeptide sequence must remain constant, therefore, if there is one “more” of one codon encoding a give amino acid, there would have to be one “less” of another codon encoding that same amino acid.

Representative fully-codon-optimized pp65 coding regions designed by this method are presented herein as SEQ ID NOs:8-10.

Additionally, a minimally codon-optimized nucleotide sequence encoding SEQ ID NO:2 can be designed by changing only certain codons found more frequently in HCMV genes than in human genes, as shown in Table 5. For example, if it is desired to substitute more frequently used codons in humans for those codons that occur at least 2.7 times more frequently in HCMV genes, Ala CGC, which occurs 2.75 times more frequently in HCMV genes than in human genes, is changed to, e.g., GCC; Pro CCG, which occurs 3.0 times more frequently in HCMV genes than is human, is changed to, e.g., CCC; Arg CGT, which occurs 3.2 times more frequently in HCMV genes than is human, is changed to, e.g., CGC; Ser TCG, which occurs 4.2 times more frequently in HCMV genes than in human, is changed to, e.g., TCC; and Thr ACG, which occurs 4.3 times more frequently in HCMV genes than is human, is changed to, e.g., ACC. The minimally codon-optimized pp65 coding region designed by this method encoding native HCMV pp65 is presented herein as SEQ ID NO:3. Other methods of “minimal” optimization can be carried out by methods well known to those of ordinary skill in the art.

In certain embodiments, the present invention provides an isolated polynucleotide comprising a nucleic acid fragment which encodes at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, or at least 100 or more contiguous amino acids of SEQ ID NO:2, where the nucleic acid fragment is a fragment of a codon-optimized coding region encoding SEQ ID NO:2. The human codon-optimized coding region can be optimized by any of the methods described herein.

In certain embodiments, the present invention provides an isolated polynucleotide comprising a nucleic acid fragment which encodes a polypeptide at least 60%, 65%, 70%, 75%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to SEQ ID NO:2, and where the nucleic acid fragment is a variant of a human codon-optimized coding region encoding SEQ ID NO:2. The human codon-optimized coding region can be optimized by any of the methods described herein.

Further provided is an isolated polynucleotide comprising a minimally codon-optimized nucleic acid (SEQ ID NO:5) which encodes a polypeptide variant of pp65, i.e., SEQ ID NO:6, in which amino acids 435-438 of SEQ ID NO:2 have been deleted. This deletion in the amino acid sequence of pp65 removes putative adventitious substrates for kinase activity present in the amino acid sequence. A human codon-optimized coding region encoding this variant can be optimized by any of the methods described herein. Alternatively amino acids 435-438 could be substituted with different amino acids, or an insertion could be made to remove the motif. Additional fragments, variants, or derivatives of SEQ ID NO:2 may be utilized as well.

The present invention further provides isolated polynucleotides comprising human codon-optimized coding regions of HCMV gB, or fragments, variants, or derivatives thereof. In certain embodiments described herein, a human codon-optimized coding region encoding SEQ ID NO:12 is optimized according to codon usage in humans (Homo sapiens). The human codon-optimized coding region can be optimized by any of the methods described herein.

Codon-optimized coding regions encoding SEQ ID NO:12, optimized according to codon usage in humans are designed as follows. The amino acid composition of SEQ ID NO:12 is shown in Table 7, and the amino acid composition of truncated, secreted gB (SEQ ID NO:14) is shown in Table 8.

TABLE 7 Amino Acid Composition of wild typo HCMV gB (SEQ ID NO: 12) Number in Amino Acid SEQ ID NO: 12 A Ala 62 R Arg 53 C Cys 16 G Gly 46 H His 20 I Ile 48 L Leu 70 K Lys 39 M Met 17 F Phe 34 P Pro 30 S Ser 87 T Thr 71 W Trp 8 Y Tyr 51 V Val 71 N Asn 52 D Asp 45 Q Gln 37 E Glu 49

TABLE 8 Amino Acid Composition of secreted HCMV gB, amino acids 1-713 (SEQ ID NO: 14) Number in Amino Acid SEQ ID NO: 14 A Ala 41 R Arg 43 C Cys 15 G Gly 27 H His 18 I Ile 41 L Leu 51 K Lys 31 M Met 15 F Phe 30 P Pro 19 S Ser 73 T Thr 56 W Trp 8 Y Tyr 43 V Val 57 N Asn 44 D Asp 35 Q Gln 25 E Glu 41

Using the amino acid composition shown in Table 7 and the human codon usage, table shown in Table 3, a human codon-optimized coding region which encodes SEQ ID NO:12 can be designed by any of the methods discussed herein. In the “uniform optimization” approach, each amino acid is assigned the most frequent codon used in the human genome for that amino acid as indicated, e.g., in Table 3. According to this method, codons are assigned to the coding region encoding SEQ ID NO:12 as follows: the 34 phenylalanine codons are TTC, the 70 leucine codons are CTG, the 48 isoleucine codons are ATC, the 17 methionine codons are ATG, the 71 valine codons are GTG, the 87 serine codons are AGC, the 30 proline codons are CCC, the 71 threonine codons are ACC, the 62 alanine codons are GCC, the 51 tyrosine codons are TAC, the 20 histidine codons are CAC, the 37 glutamine codons are CAG, the 52 asparagine codons are AAC, the 39 lysine codons are AAG, the 45 aspartic acid codons are GAC, the 49 glutamic acid codons are GAG, the 16 cysteine codons are TGC, the 8 tryptophan codons are TGG, the 53 arginine codons are CGG, AGA, or AGG (the frequencies of usage of these three codons in the human genome are not significantly different), and the 46 glycine codons are GGC. The codon-optimized full-length gB coding region designed by this method is presented herein as SEQ ID NO:15.

Alternatively, a “fully codon-optimized” coding region which encodes SEQ ID NO:12 can be designed by randomly assigning each of any given amino acid a codon based on the frequency that codon is used in the human genome. These frequencies are shown in Table 3 above. Using this latter method, codons are assigned to the coding region encoding SEQ ID NO:12 as follows: about 15 of the 34 phenylalanine codons are TTT and about 19 of the phenylalanine codons are TTC; about 5 of the 70 leucine codons are TTA, about 9 of the leucine codons are TTG, about 9 of the leucine codons are CTT, about 10 of the leucine codons are CTC, about 5 of the leucine codons are CTA, and about 28 of the leucine codons are CTG; about 17 of the 48 soleucine codons are ATT, about 23 of the isoleucine codons are ATC, and about 8 of the isoleucine codons are ATA; the 17 methionine codons are ATG; about 13 of the 71 valine codons are GTT, about 17 of the valine codons are GTC, about 8 of the valine codons are GTA, and about 33 of the valine codons are GTG; about 16 of the 87 serine codons are TCT, about 19 of the serine codons are TCC, about 13 of the serine codons are TCA, about 5 of the serine codons are TCG, about 13 of the serine codons are AGT, and about 21 of the serine codons are AGC; about 9 of the 30 proline codons are CCT, about 10 of the proline codons are CCC, about 8 of the proline codons are CCA, and about 3 of the proline codons are CCG; about 17 of the 71 threonine codons are ACT, about 26 of the threonine codons are ACC, about 20 of the threonine codons are ACA, and about 8 of the threonine codons are ACG; about 16 of the 62 alanine codons are GCT, about 25 of the alanine codons are GCC, about 14 of the alanine codons are GCA, and about 7 of the alanine codons are GCG; about 22 of the 51 tyrosine codons are TAT and about 29 of the tyrosine codons are TAC; about 8 of the 20 histidine codons are CAT and about 12 of the histidine codons are CAC; about 9 of the 37 glutamine codons are CAA and about 28 of the glutamine codons are CAG; about 24 of the 52 asparagine codons are AAT and about 28 of the asparagine codons are AAC; about 16 of the 39 lysine codons are AAA and about 23 of the lysine codons are AAG; about 21 of the 45 aspartic acid codons are GAT and about 24 of the aspartic acid codons are GAC; about 20 of the 49 glutamic acid codons are GAA and about 29 of the glutamic acid codons are GAG; about 7 of the 16 cysteine codons are TGT and about 9 of the cysteine codons are TGC; the 8 tryptophan codons are TOG; about 4 of the 53 arginine codons are CGT, about 10 of the arginine codons are CGC, about 6 of the arginine codons are CGA, about 11 of the arginine codons are CGG, about 11 of the arginine codons are AGA, and about 11 of the arginine codons are AGG; and about 7 of the 46 glycine codons are GGT, about 16 of the glycine codons are GGC, about 12 of the glycine codons are GGA, and about 11 of the glycine codons are GGG.

As described above, the term “about” means that the number of amino acids encoded by a certain codon may be one more or one less than the number given. It would be understood by those of ordinary skill in the art that the total number of any amino acid in the polypeptide sequence must remain constant, therefore, if there is one “more” of one codon encoding a give amino acid, there would have to be one “less” of another codon encoding that same amino acid. Representative fully codon-optimized gB coding regions designed by this method encoding full-length HCMV gB are presented herein as SEQ ID NOs:16-18.

Additionally, a minimally codon-optimized nucleotide sequence encoding SEQ ID NO:14 can be designed by referring to the amino acid composition of Table 8 and changing only certain codons found more frequently in highly expressing human genes, as shown in Table 5. For example, if it is desired to substitute more frequently used codons in humans for those codons that occur at least 2.7 times more frequently in HCMV genes, Ala CGC, which occurs 2.75 times more frequently in HCMV genes than in human genes, is changed to, e.g., GCC; Pro CCG, which occurs 3.0 times more frequently in HCMV genes than is human, is changed to, e.g., CCC; Arg CGT, which occurs 3.2 times more frequently in HCMV genes than is human, is changed to, e.g., CGC; Ser TCG, which occurs 4.2 times more frequently in HCMV genes than in human, is changed to, e.g., TCC; and Thr ACG, which occurs 4.3 times more frequently in HCMV genes than is human, is changed to, e.g., ACC. The minimally codon-optimized secreted gB coding region encoding SEQ ID NO:14 designed by this method is presented herein as SEQ ID NO:13.

In certain embodiments, the present invention provides an isolated polynucleotide comprising a nucleic acid fragment which encodes at least 10, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 95, or at least 100 or more contiguous amino acids of SEQ ID NO:12 or SEQ ID NO:14, where the nucleic acid fragment is a fragment of a human codon-optimized coding region encoding SEQ ID NO:12 or SEQ ID NO:14. The human codon-optimized coding region can be optimized by any of the methods described herein.

In certain embodiments, the present invention provides an isolated polynucleotide comprising a nucleic acid which encodes a polypeptide at least 60%, 65%, 70%, 75%, 80%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identical to gB, i.e., SEQ ID NO:12 or SEQ ID NO:14, and where the nucleic acid is a variant of a codon-optimized coding region encoding SEQ ID NO:12 or SEQ ID NO:14. The human codon-optimized coding region can be optimized by any of the methods described herein.

In this manner, the present invention provides a method of enhancing the level of polypeptide expression from delivered polynucleotides in vivo and/or facilitating uptake of the polynucleotides by the cells of a desired species, for example a vertebrate species, for example a mammalian species, for example humans. Accordingly, the present invention provides a method of treatment and prevention against HCMV infection.

Methods and Administration

The present invention further provides methods for delivering an HCMV polypeptide to a human, which comprise administering to a human one or more of the compositions described herein; such that upon administration of compositions such as those described herein, an HCMV polypeptide is expressed in human cells, in an amount sufficient generate an immune response to HCMV.

The term “vertebrate” is intended to encompass a singular “vertebrate” as well as plural “vertebrates” and comprises mammals and birds, as well as fish, reptiles, and amphibians.

The term “mammal” is intended to encompass a singular “mammal” and plural “mammals,” and includes, but is not limited to humans; primates such as apes, monkeys, orangutans, and chimpanzees; canids such as dogs and wolves; felids such as cats, lions, and tigers; equines such as horses, donkeys, and zebras, food animals such as cows, pigs, and sheep; ungulates such as deer and giraffes; and ursids such as bears. In particular, the mammal can be a human subject, a food animal or a companion animal.

The present invention further provides a method for generating, enhancing or modulating an immune response to HCMV comprising administering to a vertebrate one or more of the compositions described herein. In this method, the composition includes an isolated polynucleotide comprising a human codon-optimized coding region encoding a polypeptide of HCMV, or a nucleic acid fragment of such a coding region encoding a fragment, variant, or derivative thereof. The polynucleotides are incorporated into the cells of the vertebrate in vivo, and an antigenic amount of the HCMVs polypeptide, or fragment, variant, or derivative thereof, is produced in vivo. Upon administration of the composition according to this method, the HCMV polypeptide is expressed in the vertebrate in an amount sufficient to elicit an immune response. Such an immune response might be used, for example, to generate antibodies to HCMV for use in diagnostic assays or as laboratory reagents.

The present invention further provides a method for generating, enhancing, or modulating a protective and/or therapeutic immune response to HCMV in a human, comprising administering to a human in need of therapeutic and/or preventative immunity one or more of the compositions described herein. In this method, the composition includes an isolated polynucleotide comprising a human codon-optimized coding region encoding a polypeptide of HCMV, or a nucleic acid fragment of such a coding region encoding a fragment, variant, or derivative thereof. The polynucleotides are incorporated into the cells of the human in vivo, and an immunologically effective amount of the HCMV polypeptide, or fragment or variant is produced in vivo. Upon administration of the composition according to this method, the HCMV polypeptide is expressed in the human in a therapeutically or prophylactically effective amount.

As used herein, an “immune response” refers to the ability of a vertebrate to elicit an immune reaction to a composition delivered to that vertebrate. Examples of immune responses include an antibody response or a cellular, e.g., cytotoxic T-cell, response. One or more compositions of the present invention may be used to prevent HCMV infection in humans, e.g., as a prophylactic vaccine, to establish or enhance immunity to HCMV in a healthy individual prior to exposure to HCMV or contraction of HCMV disease, thus preventing the disease or reducing the severity of disease symptoms.

One or more compositions of the present invention may also be used to treat individuals already exposed to HCMV, or already suffering from HCMV disease to further stimulate the immune system of the human, thus reducing or eliminating the symptoms associated with that disease or disorder. As defined herein, “treatment” refers to the use of one or more compositions of the present invention to prevent, cure, retard, or reduce the severity of HCMV disease symptoms in a human, and/or result in no worsening of HCMV disease over a specified period of time. It is not required that any composition of the present invention provide total immunity to HCMV or totally cure or eliminate all HCMV disease symptoms. As used herein, a “human in need of therapeutic and/or preventative immunity” refers to an individual for whom it is desirable to treat, i.e., to prevent, cure, retard, or reduce the severity of HCMV disease symptoms, and/or result in no worsening of HCMV disease over a specified period of time.

In other embodiments, one or more compositions of the present invention are utilized in a “prime boost” regimen. An example of a “prime boost” regimen may be found in Yang; Z. et al. J. Virol. 77:799-803 (2002). In these embodiments, one or more polynucleotide vaccine compositions of the present invention are delivered to a human, thereby priming the immune response of the human to HCMV, and then a second immunogenic composition is utilized as a boost vaccination. One or more polynucleotide vaccine compositions of the present invention are used to prime immunity, and then a second immunogenic composition, e.g., a recombinant viral vaccine or vaccines, a different polynucleotide vaccine, one or more purified subunit HCMV proteins, e.g., gB or pp65, with or without additional HCMV antigens, e.g. IE1, or a variant, fragment, or derivative thereof, is used to boost the anti-HCMV immune response. The polynucleotide vaccine compositions may comprise one or more vectors for expression of one or more HCMV genes as described herein. In addition, a polynucleotide prime vaccine and the later boost vaccine may elicit an immune response to the same or similar antigens, or may elicit responses to different antigens.

In another embodiment, vectors are prepared for expression in the recombinant virus vaccine and in transfected mammalian cells as part of a polynucleotide vaccine.

The terms “priming” or “primary” and “boost” or “boosting” are used herein to refer to the initial and subsequent immunizations, respectively, i.e., in accordance with the definitions these terms normally have in immunology.

The invention further provides methods for enhancing the immune response of a human patient to HCMV by administering to the tissues of a human one or more polynucleotides comprising one or more codon-optimized coding regions encoding polypeptides of HCMV, and also HCMV polypeptides or fragments, variants or derivatives thereof; or one or more non-optimized polynucleotides encoding HCMV polypeptides, fragments, variants or derivatives thereof.

The combination of HCMV polypeptides or polynucleotides encoding HCMV polypeptides or fragments, variants or derivatives thereof, with the codon-optimized nucleic acid compositions provides for therapeutically beneficial effects at dose sparing concentrations. For example, immunological responses sufficient for a therapeutically beneficial effect may be attained by using less of a conventional-type vaccine (that is a vaccine comprising immunogenic polypeptides or nucleotides encoding immunogenic polypeptides, fragments, variants, or derivatives thereof, that are not products of, or have not been codon-optimized as described herein) when supplemented or enhanced with the appropriate amount of a codon-optimized nucleic acid.

Conventional-type vaccines, include vaccine compositions comprising either dead, inert or fragments of a virus or bacteria, or bacterial or viral proteins or protein fragments, injected into the patient to elicit action by the immune system. With regard to the present invention, conventional-type vaccines include compositions comprising immunogenic polypeptides or nucleotides encoding immunogenic polypeptides, fragments, variants, or derivatives thereof, and vectors comprising nucleotides encoding immunogenic polypeptides, fragments, variants, or derivatives thereof, that are not products of, or do not contain codon-optimized polynucleotides as described herein. Thus, genetically engineered vaccines, are included in conventional-type vaccines, such as genetically engineered live vaccines, live chimeric vaccines, live replication-defective vaccines, subunit vaccines, peptide vaccines in various modifications of monovalent, multivalent, or chimeric subunit vaccines delivered as individual components or incorporated into virus-like particles for improved immunogenicity, and polynucleotide vaccines. Auxiliary agents, as described herein, are also considered components of conventional-type vaccines.

Thus, dose sparing is contemplated by administration of the combinatorial polynucleotide-vaccine compositions of the present invention.

In particular, the dose of conventional-type vaccines may be reduced by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 70% when administered in combination with the codon-optimized nucleic acid compositions of the invention.

Similarly, a desirable level of an immunological response afforded by a DNA based pharmaceutical alone may be attained with less DNA by including a conventional-type DNA vaccine. Further, using a combination of a conventional-type vaccine and a codon-optimized DNA-based vaccine may allow both materials to be used in lesser amounts while still affording the desired level of immune response arising from administration of either component alone in higher amounts (e.g. one may use less of either immunological product when they are used in combination). This reduction in amounts of materials being delivered may be for each administration, in addition to reducing the number of administrations, in a vaccination regimen (e.g. 2 versus 3 or 4 injections). Further, the combination may also provide for reducing the kinetics of the immunological response (e.g. desired response levels are attained in 3 weeks instead of 6 after immunization).

In particular, the dose of DNA based pharmaceuticals, may be reduced by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 70% when administered in combination with conventional IV vaccines.

Determining the precise amounts of DNA based pharmaceutical and a conventional antigen is based on a number of factors as described herein, and is readily determined by one of ordinary skill in the art.

In addition to dose sparing, the claimed combinatorial compositions provide for a broadening of the immune response and/or enhanced beneficial immune responses. Such broadened or enhanced immune responses are achieved by: adding DNA to enhance cellular responses to a conventional-type vaccine; adding a conventional-type vaccine to a DNA pharmaceutical to enhanced humoral response; using a combination that induces additional epitopes (both humoral and/or cellular) to be recognized and/or more desirably responded to (epitope broadening); employing a DNA-conventional vaccine combination designed for a particular desired spectrum of immunological responses; obtaining a desirable spectrum by using higher amounts of either component. The broadened immune response is measurable by one of ordinary skill in the art by standard immunological assay specific for the desirable response spectrum.

Both broadening and dose sparing may be obtained simultaneously.

In certain embodiments, one or more compositions of the present invention are delivered to a human by methods described herein, thereby achieving an effective therapeutic and/or an effective preventative immune response.

More specifically, the compositions of the present invention may be administered to any tissue of a human, including, but not limited to, muscle, skin, brain tissue, lung tissue, liver tissue, spleen tissue, bone marrow tissue, thymus tissue, heart tissue, e.g., myocardium, endocardium, and pericardium, lymph tissue, blood tissue, bone tissue, pancreas tissue, kidney tissue, gall bladder tissue, stomach tissue, intestinal tissue, testicular tissue, ovarian tissue, uterine tissue, vaginal tissue, rectal tissue, nervous system tissue, eye tissue, glandular tissue, tongue tissue, and connective tissue, e.g., cartilage.

Furthermore, the compositions of the present invention may be administered to any internal cavity of a human, including, but not limited to, the lungs, the mouth, the nasal cavity, the stomach, the peritoneal cavity, the intestine, any heart chamber, veins, arteries, capillaries, lymphatic cavities, the uterine cavity, the vaginal cavity, the rectal cavity, joint cavities, ventricles in brain, spinal canal in spinal cord, the ocular cavities, the lumen of a duct of a salivary gland or a liver. When the compositions of the present invention is administered to the lumen of a duct of a salivary gland or liver, the desired polypeptide is expressed in the salivary gland and the liver such that the polypeptide is delivered into the blood stream of the human from each of the salivary gland or the liver. Certain modes for administration to secretory organs of a gastrointestinal system using the salivary gland, liver and pancreas to release a desired polypeptide into the bloodstream is disclosed in U.S. Pat. Nos. 5,837,693 and 6,004,944, both of which are incorporated herein by reference in their entireties.

In one embodiment, the compositions are administered to muscle, either skeletal muscle or cardiac muscle, or to lung tissue. Specific, but non-limiting modes for administration to lung tissue are disclosed in Wheeler, C. J., et al., Proc. Natl. Acad. Sci. USA 93:11454-11459 (1996), which is incorporated herein by reference in its entirety.

According to the disclosed methods, compositions of the present invention can be administered by intramuscular (i.m.), subcutaneous (s.c.), or intrapulmonary routes. Other suitable routes of administration include, but not limited to intratracheal, transdermal, intraocular, intranasal, inhalation, intracavity, intravenous (i.v.), intraductal (e.g., into the pancreas) and intraparenchymal (i.e., into any tissue) administration. Transdermal delivery includes, but not limited to intradermal (e.g., into the dermis or epidermis), transdermal (e.g., percutaneous) and transmucosal administration (i.e., into or through skin or mucosal tissue). Intracavity administration includes, but not limited to administration into oral, vaginal, rectal; nasal, peritoneal, or intestinal cavities as well as, intrathecal (i.e., into spinal canal), intraventricular (i.e., into the brain ventricles or the heart ventricles), intraatrial (i.e., into the heart atrium) and sub arachnoid (i.e., into the sub arachnoid spaces of the brain) administration.

Any mode of administration can be used so long as the mode results in the expression of the desired peptide or protein, in the desired tissue, in an amount sufficient to generate an immune response to HCMV and/or to generate a prophylactically or therapeutically effective immune response to HCMV in a human in need of such response. Administration means of the present invention include needle injection, catheter infusion, biolistic injectors, particle accelerators (e.g., “gene guns” or pneumatic “needleless” injectors) Med-E-Jet (Vahlsing, H., et al., J. Immunol. Methods 171:11-22 (1994)), Pigjet (Schrijver, R., et al., Vaccine 15: 1908-1916 (1997)), Biojector (Davis, H., et al., Vaccine 12: 1503-1509 (1994); Gramzinski, R., et al., Mol. Med. 4: 109-118 (1998)), Advantajet (Linmayer, I., et al., Diabetes Care 9:294-297 (1986)), Medi-jector (Martins, J., and Roedl, E. J. Occup. Med. 21:821-824 (1979)), gelfoam sponge depots, other commercially available depot materials (e.g., hydrogels), osmotic pumps (e.g., Alza minipumps), oral or suppositorial solid (tablet or pill) pharmaceutical formulations, topical skin creams, and decanting, use of polynucleotide coated suture (Qin, Y., et al., Life Sciences 65: 2193-2203 (1999)) or topical applications during surgery. Certain modes of administration are intramuscular needle-based injection and pulmonary application via catheter infusion. Energy-assisted plasmid delivery (EAPD) methods may also be employed to administer the compositions of the invention. One such method involves the application of brief electrical pulses to injected tissues, a procedure commonly known as electroporation. See generally Mir, L. M. et al., Proc. Natl. Acad. Sci USA 96:4262-7 (1999); Hartikka, J. et al., Mol. Ther. 4:407-15 (2001); Mathiesen, I., Gene Ther. 6:508-14 (1999); Rizzuto G. et al., Hum. Gen. Ther. 11:1891-900 (2000). Each of the references cited in this paragraph is incorporated herein by reference in its entirety.

Further, antigen constructs alone or in combination may be formulated to enhance the type of immune response (e.g. humoral, cellular, mucosal, etc.) believed to be most beneficial to mount in the host for that particular antigen or antigens. Each such formulation may be administered individually at a separate site in the host, and/or combined and administered with some or all of the other antigen formulations at one or more sites in the host. Each administration may be accomplished using the same or different physical means of administration. Thus, as a non-limiting example, a gB plasmid could be formulated with cationic lipids and administered as a mist intranasaly, in conjunction with administration of a poloxamer formulation of pp65 using a needle free device into skin and muscle of one limb, in conjunction with trans-dermal intramuscular administration using a conventional syringe and needle of an IE1 plasmid in PBS into a second limb.

Determining an effective amount of one or more compositions of the present invention depends upon a number of factors including, for example, the antigen being expressed, e.g. gB, pp65 or IE1; or fragments, variants, or derivatives thereof, the age and weight of the subject, the precise condition requiring treatment and its severity, and the route of administration. Based on the above factors, determining the precise amount, number of doses, and timing of doses are within the ordinary skill in the art and will be readily determined by the attending physician.

Compositions of the present invention may include various salts, excipients, delivery vehicles and/or auxiliary agents as are disclosed, e.g., in U.S. Patent Application Publication 2002/0019358, published Feb. 14, 2002, which is incorporated herein by reference in its entirety.

Furthermore, compositions of the present invention may include one or more transfection facilitating compounds that facilitate delivery of polynucleotides to the interior of a cell, and/or to a desired location within a cell. As used herein, the terms “transfection facilitating compound,” “transfection facilitating agent,” and “transfection facilitating material” are synonymous, and may be used interchangeably. It should be noted that certain transfection facilitating compounds may also be “adjuvants” as described infra, e.g., in addition to facilitating delivery of polynucleotides to the interior of a cell, the compound acts to alter or increase the immune response to the antigen encoded by that polynucleotide. Examples of the transfection facilitating compounds include, but are not limited to inorganic materials such as calcium phosphate, alum (aluminum sulfate), and gold particles (e.g., “powder” type delivery vehicles); peptides that are, for example, cationic, intercell targeting (for selective delivery to certain cell types), intracell targeting (for nuclear localization or endosomal escape), and ampipathic (helix forming or pore forming); proteins that are, for example, basic (e.g., positively charged) such as histones, targeting (e.g., asialoprotein), viral (e.g., Sendai virus coat protein), and pore-forming; lipids that are, for example, cationic (e.g., DMRIE, DOSPA, DC-Chol), basic (e.g., steryl amine), neutral (e.g., cholesterol), anionic (e.g., phosphatidyl serine), and zwitterionic (e.g., DOPE, DOPC); and polymers such as dendrimers, star-polymers, “homogenous” poly-amino acids (e.g., poly-lysine, poly-arginine), “heterogenous” poly amino acids (e.g., mixtures of lysine & glycine), co-polymers, polyvinylpyrrolidinone (PVP), poloxamers (e.g. CRL 1005) and polyethylene glycol (PEG). A transfection facilitating material can be used alone or in combination with one or more other transfection facilitating materials. Two or more transfection facilitating materials can be combined by chemical bonding (e.g., covalent and ionic such as in lipidated polylysine, PEGylated polylysine) (Toncheva, et al., Biochim. Biophys. Acta 1380(3):354-368 (1988)), mechanical mixing (e.g., free moving materials in liquid or solid phase such as “polylysine+cationic lipids”) (Gao and Huang, Biochemistry 35:1027-1036 (1996); Trubetskoy, et al., Biochem. Biophys. Acta 1131:311-313 (1992)), and aggregation (e.g., co-precipitation, gel forming such as in cationic lipids+poly-lactide, and polylysine+gelatin).

One category of transfection facilitating materials is cationic lipids. Examples of cationic lipids are 5-carboxyspermylglycine dioctadecylamide (DOGS) and dipalmitoyl-phophatidylethanolamine-5-carboxyspermylamide (DPPES). Cationic cholesterol derivatives are also useful, including {3β-[N—N′,N′-dimethylamino)ethane]-carbomoyl}-cholesterol(DC-Chol). Dimethyldioctdecyl-ammonium bromide (DDAB), N-(3-aminopropyl)-N,N-(bis-(2-tetradecyloxyethyl))-N-methyl-ammonium bromide (PA-DEMO), N-(3-aminopropyl)-N,N-(bis-(2-dodecyloxyethyl))-N-methyl-ammonium bromide (PA-DELO), N,N,N-tris-(2-dodecyloxy)ethyl-N-(3-amino)propyl-ammonium bromide (PA-TELO), and N1-(3-aminopropyl)((2-dodecyloxy)ethyl)-N2-(2-dodecyloxy)ethyl-1-piperazinaminium bromide (GA-LOE-BP) can also be employed in the present invention.

Non-diether cationic lipids, such as DL-1,2-dioleoyl-3-dimethylaminopropyl-β-hydroxyethylammonium (DORI diester), 1-O-oleyl-2-oleoyl-3-dimethylaminopropyl-β-hydroxyethylammonium (DORI ester/ether), and their salts promote in vivo gene delivery. In some embodiments, cationic lipids comprise groups attached via a heteroatom attached to the quaternary ammonium moiety in the head group. A glycyl spacer can connect the linker to the hydroxyl group.

Specific, but non-limiting cationic lipids for use in certain embodiments of the present invention include DMRIE ((±)-N-(2-hydroxyethyl)-N,N-dimethyl-2,3-bis(tetradecyloxy)-1-propanaminium bromide), GAP-DMORIE ((±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(syn-9-tetradeceneyloxy)-1-propanaminium bromide), and GAP-DLRIE ((±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-(bis-dodecyloxy)-1-propanaminium bromide).

Other specific but non-limiting cationic surfactants for use in certain embodiments of the present invention include Bn-DHRIE, DhxRIE, DhxRIE-OAc, DhxRIE-OBz and Pr-DOctRIE-OAc. These lipids are disclosed in copending U.S. Patent Application Ser. No. 60/435,303. In another aspect of the present invention, the cationic surfactant is Pr-DOctRIE-OAc.

Other cationic lipids include (±)-N,N-dimethyl-N-[2-(sperminecarboxamido)ethyl]-2,3-bis(dioleyloxy)-1-propaniminium pentahydrochloride (DOSPA), (±)-N-(2-aminoethyl)-N,N-dimethyl-2,3-bis(tetradecyloxy)-1-propaniminium bromide(β-aminoethyl-DMRIE or RAE-DMRIE) (Wheeler, et al., Biochim. Biophys. Acta 1280:1-11 (1996)), and (±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propaniminium bromide (GAP-DLRIE) (Wheeler, et al., Proc. Natl. Acad. Sci. USA 93:11454-11459 (1996)), which have been developed from DMRIE.

Other examples of DMRIE-derived cationic lipids that are useful for the present invention are (±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-(bis-decyloxy)-1-propanaminium bromide (GAP-DDRIE), (±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-(bis-tetradecyloxy)-1-propanaminium bromide (GAP-DMRIE), (±)-N—((N″-methyl)-N′-ureyl)propyl-N,N-dimethyl-2,3-bis(tetradecyloxy)-1-propanaminium bromide (GMU-DMRIE), (±)-N-(2-hydroxyethyl)-N,N-dimethyl-2,3-bis(dodecyloxy)-1-propanaminium bromide (DLRIE), and (±)-N-(2-hydroxyethyl)-N,N-dimethyl-2,3-bis-([Z]-9-octadecenyloxy)propyl-1-propaniminium bromide (HP-DORIE).

In the embodiments where the immunogenic composition comprises a cationic lipid, the cationic lipid may be mixed with one or more co-lipids. For purposes of definition, the term Aco-lipid refers to any hydrophobic material which may be combined with the cationic lipid component and includes amphipathic lipids, such as phospholipids, and neutral lipids, such as cholesterol. Cationic lipids and co-lipids may be mixed or combined in a number of ways to produce a variety of non-covalently bonded macroscopic structures, including, for example, liposomes, multilamellar vesicles, unilamellar vesicles, micelles, and simple films. One non-limiting class of co-lipids are the zwitterionic phospholipids, which include the phosphatidylethanolamines and the phosphatidylcholines. Examples of phosphatidylethanolamines, include DOPE, DMPE and DPyPE. In certain embodiments, the co-lipid is DPyPE, which comprises two phytanoyl substituents incorporated into the diacylphosphatidylethanolamine skeleton. In other embodiments, the co-lipid is DOPE, CAS name 1,2-diolyeoyl-sn-glycero-3-phosphoethanolamine.

When a composition of the present invention comprises a cationic lipid and co-lipid, the cationic lipid:co-lipid molar ratio may be from about 9:1 to about 1:9, from about 4:1 to about 1:4, from about 2:1 to about 1:2, or about 1:1.

In order to maximize homogeneity, the plasmid and co-lipid components may be dissolved in a solvent such as chloroform, followed by evaporation of the cationic lipid/co-lipid solution under vacuum to dryness as a film on the inner surface of a glass vessel (e.g., a Rotovap round-bottomed flask). Upon suspension in an aqueous solvent, the amphipathic lipid component molecules self-assemble into homogenous lipid vesicles. These lipid vesicles may subsequently be processed to have a selected mean diameter of uniform size prior to complexing with, for example, a codon-optimized polynucleotide of the present invention, according to methods known to those skilled in the art. For example, the sonication of a lipid solution is described in Felgner et al., Proc. Natl. Acad. Sci. USA 8:7413-7417 (1987) and in U.S. Pat. No. 5,264,618, the disclosures of which are incorporated herein by reference.

In those embodiments where the composition includes a cationic lipid, polynucleotides of the present invention are complexed with lipids by mixing, for example, a plasmid in aqueous solution and a solution of cationic lipid:co-lipid as prepared herein are mixed. The concentration of each of the constituent solutions can be adjusted prior to mixing such that the desired final plasmid/cationic lipid:co-lipid ratio and the desired plasmid final concentration will be obtained upon mixing the two solutions. The cationic lipid:co-lipid mixtures are suitably prepared by hydrating a thin film of the mixed lipid materials in an appropriate volume of aqueous solvent by vortex mixing at ambient temperatures for about 1 minute. The thin films are prepared by admixing chloroform solutions of the individual components to afford a desired molar solute ratio followed by aliquoting the desired volume of the solutions into a suitable container. The solvent is removed by evaporation, first with a stream of dry, inert gas (e.g. argon) followed by high vacuum treatment.

Other hydrophobic and amphiphilic additives, such as, for example, sterols, fatty acids, gangliosides, glycolipids, lipopeptides, liposaccharides, neobees, niosomes, prostaglandins and sphingolipids, may also be included in compositions of the present invention. In such compositions, these additives may be included in an amount between about 0.1 mol % and about 99.9 mol % (relative to total lipid), about 1-50 mol %, or about 2-25 mol %.

Additional embodiments of the present invention are drawn to compositions comprising an auxiliary agent which is administered before, after, or concurrently with the polynucleotide. As used herein, an “auxiliary agent” is a substance included in a composition for its ability to enhance, relative to a composition which is identical except for the inclusion of the auxiliary agent, the entry of polynucleotides into vertebrate cells in vivo, and/or the in vivo expression of polypeptides encoded by such polynucleotides. Certain auxiliary agents may, in addition to enhancing entry of polynucleotides into cells, enhance an immune response to an immunogen encoded by the polynucleotide. Auxiliary agents of the present invention include nonionic, anionic, cationic, or zwitterionic surfactants or detergents; chelators, DNAse inhibitors, poloxamers, agents that aggregate or condense nucleic acids, emulsifying or solubilizing agents, wetting agents, gel-forming agents, and buffers.

Auxiliary agents for use in compositions of the present invention include, but are not limited to non-ionic detergents and surfactants IGEPAL CA 630® CA 630, NONIDET® NP-40, NONIDET® P40 (2-[2-[4-(2,4,4-trimethylpentan-2-yl)phenoxyl]ethoxyl]ethanol), TWEEN-20™ (2-[2-[3,4-bis(2-hydroxyethoxy)oxolan-2-yl]-2-(2-hydroxyethoxy)ethoxy]ethyl dodecanoate), TWEEN-80™, Pluronic® F68, Pluronic® F77, Pluronic® P65, Triton X-100™, and Triton X-114™; the anionic detergent sodium dodecyl sulfate (SDS); the sugar stachyose; the condensing agent DMSO; and the chelator/DNAse inhibitor EDTA, CRL 1005, and BAK. In certain specific embodiments, the auxiliary agent is DMSO, NONIDET® P40 (2-[2-[4-(2,4,4-trimethylpentan-2-yl)phenoxy]ethoxy]ethanol), Pluronic® F68, Pluronic® F77, Pluronic® P65, Pluronic® L64, and Pluronic® F108. See, e.g., U.S. Patent Application Publication 20020019358, published Feb. 14, 2002, which is incorporated herein by reference in its entirety.

Certain compositions of the present invention may further include one or more adjuvants before, after, or concurrently with the polynucleotide. The term “adjuvant” refers to any material having the ability to (1) alter or increase the immune response to a particular antigen or (2) increase or aid an effect of a pharmacological agent. It should be noted, with respect to polynucleotide vaccines, that an “adjuvant,” may be a transfection facilitating material. Similarly, certain “transfection facilitating materials” described supra, may also be an “adjuvant.” An adjuvant may be used with a composition comprising a polynucleotide of the present invention. In a prime-boost regimen, as described herein, an adjuvant may be used with either the priming immunization, the booster immunization, or both. Suitable adjuvants include, but are not limited to, cytokines and growth factors; bacterial components (e.g., endotoxins, in particular superantigens, exotoxins and cell wall components); aluminum-based salts; calcium-based salts; silica; polynucleotides; toxoids; serum proteins, viruses and virally-derived materials, poisons, venoms, poloxamers, and cationic lipids.

A great variety of materials have been shown to have adjuvant activity through a variety of mechanisms. Any compound which may increase the expression, antigenicity or immunogenicity of the polypeptide is a potential adjuvant. The present invention provides an assay to screen for improved immune responses to potential adjuvants. Potential adjuvants which may be screened for their ability to enhance the immune response according to the present invention include, but are not limited to: inert carriers, such as alum, bentonite, latex, and acrylic particles; pluronic block polymers, such as TiterMax™; depot formers, such as Freunds adjuvant, surface active materials, such as saponin, lysolecithin, retinal, Quil A, liposomes, and pluronic polymer formulations; macrophage stimulators, such as bacterial lipopolysaccharide; alternate pathway complement activators; such as insulin, zymosan, endotoxin, and levamisole; and non-ionic surfactants, such as poloxamers, poly(oxyethylene)-poly(oxypropylene)tri-block copolymers. Also included as adjuvants are transfection-facilitating materials, such as those described above.

Poloxamers which may be screened for their ability to enhance the immune response according to the present invention include, but are not limited to commercially available poloxamers such as Pluronic® L121 (ave. MW: 4400; approx. MW of hydrophobe, 3600; approx. wt. % of hydrophile, 10%), Pluronic® L101 (ave. MW: 3800; approx. MW of hydrophobe, 3000; approx. wt. % of hydrophile, 10%), Pluronic® L81 (ave. MW: 2750; approx. MW of hydrophobe, 2400; approx. wt. % of hydrophile, 10%), Pluronic® L61 (ave. MW: 2000; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 10%), Pluronic® L31 (ave. MW: 1100; approx. MW of hydrophobe, 900; approx. wt. % of hydrophile, 10%), Pluronic® L122 (ave. MW: 5000; approx. MW of hydrophobe, 3600; approx. wt. % of hydrophile, 20%), Pluronic® L92 (ave. MW: 3650; approx. MW of hydrophobe, 2700; approx. wt. % of hydrophile; 20%), Pluronic® L72 (ave. MW: 2750; approx. MW of hydrophobe, 2100; approx. wt. % of hydrophile, 20%), Pluronic® L62 (ave. MW: 2500; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 20%), Pluronic® L42 (ave. MW: 1630; approx. MW of hydrophobe, 1200; approx. wt. % of hydrophile, 20%), Pluronic® L63 (ave. MW: 2650; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 30%), Pluronic® L43 (ave. MW: 1850; approx. MW of hydrophobe, 1200; approx. wt. % of hydrophile, 30%), Pluronic® L64 (ave. MW: 2900; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 40%), Pluronic® L44 (ave. MW: 2200; approx. MW of hydrophobe, 1200; approx. wt. % of hydrophile, 40%), Pluronic® L35 (ave. MW: 1900; approx. MW of hydrophobe, 900; approx. wt. % of hydrophile, 50%), Pluronic® P123 (ave. MW: 5750; approx. MW of hydrophobe, 3600; approx. wt. % of hydrophile, 30%), Pluronic® P103 (ave. MW: 4950; approx. MW of hydrophobe, 3000; approx. wt. % of hydrophile, 30%), Pluronic® P104 (ave. MW: 5900; approx. MW of hydrophobe, 3000; approx. wt. % of hydrophile, 40%), Pluronic® P84 (ave. MW: 4200; approx. MW of hydrophobe, 2400; approx. wt. % of hydrophile, 40%), Pluronic® P105 (ave. MW: 6500; approx. MW of hydrophobe, 3000; approx. wt. % of hydrophile, 50%), Pluronic® P85 (ave. MW: 4600; approx. MW of hydrophobe, 2400; approx. wt. % of hydrophile, 50%), Pluronic® P75 (ave. MW: 4150; approx. MW of hydrophobe, 2100; approx. wt. % of hydrophile, 50%), Pluronic® P65 (ave. MW: 3400; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 50%), Pluronic® F127 (ave. MW: 12600; approx. MW of hydrophobe, 3600; approx. wt. % of hydrophile, 70%), Pluronic® F98 (ave. MW: 13000; approx. MW of hydrophobe, 2700; approx. wt. % of hydrophile, 80%), Pluronic® F87 (ave. MW: 7700; approx. MW of hydrophobe, 0.2400; approx. wt. % of hydrophile, 70%), Pluronic® F77 (ave. MW: 6600; approx. MW of hydrophobe, 2100; approx. wt. % of hydrophile, 70%), Pluronic® F108 (ave. MW: 14600; approx. MW of hydrophobe, 3000; approx. wt. % of hydrophile, 80%), Pluronic® F98 (ave. MW: 13000; approx. MW of hydrophobe, 2700; approx. wt. % of hydrophile, 80%), Pluronic® F88 (ave. MW: 11400; approx. MW of hydrophobe, 2400; approx. wt. % of hydrophile, 80%), Pluronic® F68 (ave. MW: 8400; approx. MW of hydrophobe, 1800; approx. wt. % of hydrophile, 80%), Pluronic® F38 (ave. MW: 4700; approx. MW of hydrophobe, 900; approx. wt. % of hydrophile, 80%).

Reverse poloxamers of the present invention include, but are not limited to Pluronic® R 31R1 (ave. MW: 3250; approx. MW of hydrophobe, 3100; approx. wt. % of hydrophile, 10%), Pluronic® R 25R1 (ave. MW: 2700; approx. MW of hydrophobe, 2500; approx. wt. % of hydrophile, 10%), Pluronic® R 17R1 (ave. MW: 1900; approx. MW of hydrophobe, 1700; approx. wt. % of hydrophile, 10%), Pluronic® R 31R2 (ave. MW: 3300; approx. MW of hydrophobe, 3100; approx. wt: % of hydrophile, 20%), Pluronic® R 25R2 (ave. MW: 3100; approx. MW of hydrophobe, 2500; approx. wt. % of hydrophile, 20%), Pluronic® R 17R2 (ave. MW: 2150; approx. MW of hydrophobe, 1700; approx. wt. % of hydrophile, 20%), Pluronic® R 12R3 (ave. MW: 1800; approx. MW of hydrophobe, 1200; approx. wt. % of hydrophile, 30%), Pluronic® R 31R4 (ave. MW: 4150; approx. MW of hydrophobe, 3100; approx. wt. % of hydrophile, 40%), Pluronic® R 25R4 (ave. MW: 3600; approx. MW of hydrophobe, 2500; approx. wt. % of hydrophile, 40%), Pluronic® R 22R4 (ave. MW: 3350; approx. MW of hydrophobe, 2200; approx. wt. % of hydrophile, 40%), Pluronic® R 17R4 (ave. MW: 3650; approx. MW of hydrophobe, 1700; approx. wt. % of hydrophile, 40%), Pluronic® R 25R5 (ave. MW: 4320; approx. MW of hydrophobe, 2500; approx. wt. % of hydrophile, 50%), Pluronic® R 10R5 (ave. MW: 1950; approx. MW of hydrophobe, 1000; approx. wt. % of hydrophile, 50%), Pluronic® R 25R8 (ave. MW: 8550; approx. MW of hydrophobe, 2500; approx. wt. % of hydrophile, 80%), Pluronic® R 17R8 (ave. MW: 7000; approx. MW of hydrophobe, 1700; approx. wt. % of hydrophile, 80%), and Pluronic® R 10R8. (ave. MW: 4550; approx. MW of hydrophobe, 1000; approx. wt. % of hydrophile, 80%).

Other commercially available poloxamers which may be screened for their ability to enhance the immune response according to the present invention include compounds that are block copolymer of polyethylene and polypropylene glycol such as Synperonic® L121, Synperonic® L122, Synperonic® P104, Synperonic® P105, Synperonic® P123, Synperonic® P85 and Synperonic® P94; and compounds that are nonylphenyl polyethylene glycol such as Synperonic® NP10, Synperonic® NP30 and Synperonic® NP5.

Other poloxamers which may be screened for their ability to enhance the immune response according to the present invention include a polyether block copolymer comprising an A-type segment and a B-type segment, wherein the A-type segment comprises a linear polymeric segment of relatively hydrophilic character, the repeating units of which contribute an average Hansch-Leo fragmental constant of about −0.4 or less and have molecular weight contributions between about 30 and about 500, wherein the B-type segment comprises a linear polymeric segment of relatively hydrophobic character, the repeating units of which contribute an average Hansch-Leo fragmental constant of about −0.4 or more and have molecular weight contributions between about 30 and about 500, wherein at least about 80% of the linkages joining the repeating units for each of the polymeric segments comprise an ether linkage; (b) a block copolymer having a polyether segment and a polycation segment, wherein the polyether segment comprises at least an A-type block, and the polycation segment comprises a plurality of cationic repeating units; and (c) a polyether-polycation copolymer comprising a polymer, a polyether segment and a polycationic segment comprising a plurality of cationic repeating units of formula —NH—R⁰, wherein R⁰ is a straight chain aliphatic group of 2 to 6 carbon atoms, which may be substituted, wherein said polyether segments comprise at least one of an A-type of B-type segment. See U.S. Pat. No. 5,656,611, by Kabonov, et al., which is incorporated herein by reference in its entirety.

Other auxiliary agents which may be screened for their ability to enhance the immune response according to the present invention include, but are not limited to Acacia (gum arabic); the poloxyethylene ether R—O—(C₂H₄O)_(x)—H (BRIJ®), e.g., polyethylene glycol dodecyl ether (BRIJ® 35, x=23), polyethylene glycol dodecyl ether (BRIJ® 30, x=4), polyethylene glycol hexadecyl ether (BRIJ® 52 x=2), polyethylene glycol hexadecyl ether (BRIJ® 56, x=10), polyethylene glycol hexadecyl ether (BRIJ® 58P, x=20), polyethylene glycol octadecyl ether (BRIJ® 72, x=2), polyethylene glycol octadecyl ether (BRIJ® 76, x=10), polyethylene glycol octadecyl ether (BRIJ® 78P, x=20), polyethylene glycol oleyl ether (BRIJ® 92V, x=2), and polyoxyl 10 oleyl ether (BRIJ® 97, x=10); poly-D-glucosamine (chitosan); chlorbutanol; cholesterol; diethanolamine; digitonin; dimethylsulfoxide (DMSO), ethylenediamine tetraacetic acid (EDTA); glyceryl monosterate; lanolin alcohols; mono- and di-glycerides; monoethanolamine; nonylphenol polyoxyethylene ether (NP-40®); octylphenoxypolyethoxyethanol (NONIDET NP-40 from Amresco); ethyl phenol poly(ethylene glycol ether)^(n), n=11 (Nonidet® P40 from Roche); octyl phenol ethylene oxide condensate with about 9 ethylene oxide units (nonidet P40); IGEPAL CA 630® ((octyl phenoxy)polyethoxyethanol; structurally same as NONIDET NP-40); oleic acid; oleyl alcohol; polyethylene glycol 8000; polyoxyl 20 cetostearyl ether; polyoxyl 35 castor oil; polyoxyl 40 hydrogenated castor oil; polyoxyl 40 stearate; polyoxyethylene sorbitan monolaurate (polysorbate 20, or TWEEN-20®; polyoxyethylene sorbitan monooleate (polysorbate 80, or TWEEN-80®); propylene glycol diacetate; propylene glycol monstearate; protamine sulfate; proteolytic enzymes; sodium dodecyl sulfate (SDS); sodium monolaurate; sodium stearate; sorbitan derivatives (SPAN®), e.g., sorbitan monopalmitate (SPAN® 40), sorbitan monostearate (SPAN® 60), sorbitan tristearate (SPAN® 65), sorbitan monooleate (SPAN® 80), and sorbitan trioleate (SPAN® 85); 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosa-hexaene (squalene); stachyose; stearic acid; sucrose; surfactin (lipopeptide antibiotic from Bacillus subtilis); dodecylpoly(ethyleneglycolether)₉ (Thesit®) MW 582.9; octyl phenol ethylene oxide condensate with about 9-10 ethylene oxide units (Triton X-100™); octyl phenol ethylene oxide condensate with about 7-8 ethylene oxide units (Triton X-114™); tris(2-hydroxyethyl)amine (trolamine); and emulsifying wax.

In certain adjuvant compositions, the adjuvants are cytokines. A composition of the present invention can comprise one or more cytokines, chemokines, or compounds that induce the production of cytokines and chemokines, or a polynucleotide encoding one or more cytokines, chemokines, or compounds that induce the production of cytokines and chemokines. Examples include, but are not limited to granulocyte macrophage colony stimulating factor (GM-CSF), granulocyte colony stimulating factor (G-CSF), macrophage colony stimulating factor (M-CSF), colony stimulating factor (CSF), erythropoietin (EPO), interleukin 2 (IL-2), interleukin-3 (IL-3), interleukin 4 (IL-4), interleukin 5 (IL-5), interleukin 6 (IL-6), interleukin 7 (IL-7), interleukin 8 (IL-8), interleukin 10 (IL-10), interleukin 12 (IL-12), interleukin 15 (IL-15), interleukin 18 (IL-18), interferon alpha (IFNα), interferon beta (IFNβ), interferon gamma (IFNγ), interferon omega (IFNω), interferon tau (IFNτ), interferon gamma inducing factor I (IGIF), transforming growth factor beta (TGF-β), RANTES (regulated upon activation, normal T-cell expressed and presumably secreted), macrophage inflammatory proteins (e.g., MIP-1 alpha and MIP-1 beta), Leishmania elongation initiating factor (LEIF), and Flt-3 ligand.

In certain compositions of the present invention, the polynucleotide construct may be complexed with an adjuvant composition comprising (±)-N-(3-aminopropyl)-N,N-dimethyl-2,3-bis(syn-9-tetradeceneyloxy)-1-propanaminium bromide (GAP-DMORIE). The composition may also comprise one or more co-lipids, e.g., 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), 1,2-diphytanoyl-sn-glycero-3-phosphoethanolamine (DPyPE), and/or 1,2-dimyristoyl-glycer-3-phosphoethanolamine (DMPE). An adjuvant composition comprising; GAP-DMORIE and DPyPE at a 1:1 molar ratio is referred to herein as Vaxfectin™. See, e.g., PCT Publication No. WO 00/57917, which is incorporated herein by reference in its entirety.

The ability of an adjuvant to increase the immune response to an antigen is typically manifested by a significant increase in immune-mediated protection. For example, an increase in humoral immunity is typically manifested by a significant increase in the titer of antibodies raised to the antigen, and an increase in T-cell activity is typically manifested in increased cell proliferation, increased cytokine production and/or antigen specific cytolytic activity. An adjuvant may also alter an immune response, for example, by changing a Th₂ response into a Th₁ response.

Nucleic acid molecules and/or polynucleotides of the present invention, e.g., pDNA, mRNA, linear DNA or oligonucleotides, may be solubilized in any of various buffers. Suitable buffers include, for example, phosphate buffered saline (PBS), normal saline, Tris buffer, and sodium phosphate (e.g., 150 mM sodium phosphate). Insoluble polynucleotides may be solubilized in a weak acid or weak base, and then diluted to the desired volume with a buffer. The pH of the buffer may be adjusted as appropriate. In addition, a pharmaceutically acceptable additive can be used to provide an appropriate osmolarity. Such additives are within the purview of one skilled in the art. For aqueous compositions used in vivo, sterile pyrogen-free water can be used. Such formulations will contain an effective amount of a polynucleotide together with a suitable amount of an aqueous solution in order to prepare pharmaceutically acceptable compositions suitable for administration to a human.

Compositions of the present invention can be formulated according to known methods. Suitable preparation methods are described, for example, in Remington's Pharmaceutical Sciences, 16th Edition, A. Osol, ed., Mack Publishing Co., Easton, Pa. (1980), and Remington's Pharmaceutical Sciences, 19th Edition, A. R. Gennaro, ed., Mack Publishing Co., Easton, Pa. (1995), both of which are incorporated herein by reference in their entireties. Although the composition may be administered as an aqueous solution, it can also be formulated as an emulsion, gel, solution, suspension, lyophilized form, or any other form known in the art. In addition, the composition may contain pharmaceutically acceptable additives including, for example, diluents, binders, stabilizers, and preservatives.

The following examples are included for purposes of illustration only and are not intended to limit the scope of the present invention, which is defined by the appended claims. All references cited in the Examples are incorporated herein by reference in their entireties.

EXAMPLES Materials and Methods

The following materials and methods apply generally to all the examples disclosed herein. Specific materials and methods are disclosed in each example, as necessary.

The practice of the present invention will employ, unless otherwise indicated, conventional techniques of cell biology, cell culture, molecular biology (including PCR), vaccinology, microbiology, recombinant DNA, and immunology, which are within the skill of the art. Such techniques are explained fully in the literature. See, for example, Molecular Cloning A Laboratory Manual, 2nd Ed., Sambrook et al., ed., Cold Spring Harbor Laboratory Press: (1989); DNA Cloning, Volumes I and II (D. N. Glover ed., 1985); Oligonucleotide Synthesis (M. J. Gait ed., 1984); Mullis et al. U.S. Pat. No. 4,683,195; Nucleic Acid Hybridization (B. D. Hames & S. J. Higgins eds. 1984); Transcription And Translation (B. D. Hames & S. J. Higgins eds: 1984); Culture Of Animal Cells (R. I. Freshney, Alan R. Liss, Inc., 1987); Immobilized Cells And Enzymes (IRL Press, 1986); B. Perbal, A Practical Guide To Molecular Cloning (1984); the treatise, Methods In Enzymology (Academic Press, Inc., N.Y.); Gene Transfer Vectors For Mammalian Cells (J. H. Miller and M. P. Calos eds., 1987, Cold Spring Harbor Laboratory); Methods In Enzymology, Vols. 154 and 155 (Wu et al. eds.), Immunochemical Methods In Cell And Molecular Biology (Mayer and Walker, eds., Academic Press, London, 1987); and in Ausubel et al., Current Protocols in Molecular Biology, John Wiley and Sons, Baltimore, Md. (1989).

Gene Construction

Constructs of the present invention are constructed based on the sequence information provided herein or in the art utilizing standard molecular biology techniques, including, but not limited to the following. First, a series complementary oligonucleotide pairs of 80-90 nucleotides each in length and spanning the length of the construct are synthesized by standard methods. These oligonucleotide pairs are synthesized such that upon annealing, they form double stranded fragments of 80-90 base pairs, containing cohesive ends. The single-stranded ends of each pair of oligonucleotides are designed to anneal with a single-stranded end of an adjacent oligonucleotide duplex. Several adjacent oligonucleotide pairs prepared in this manner are allowed to anneal, and approximately five to six adjacent oligonucleotide duplex fragments are then allowed to anneal together via the cohesive single stranded ends. This series of annealed oligonucleotide duplex fragments is then ligated together and cloned into a suitable plasmid, such as the TOPO® vector available from Invitrogen Corporation, Carlsbad, Calif. The construct is then sequenced by standard methods. Constructs prepared in this manner, comprising 5 to 6 adjacent 80 to 90 base pair fragments ligated together, i.e., fragments of about 500 base pairs, are prepared, such that the entire desired sequence of the construct is represented in a series of plasmid constructs. The inserts of these plasmids are then cut with appropriate restriction enzymes and ligated together to form the final construct. The final construct is then cloned into a standard bacterial cloning vector, and sequenced. Alternatively, wild sequences can be cloned directly from HCMV-infected cells (e.g. MRC-5 cells, ATCC Accession No. CCL-171, available from the American Type Culture Collection, Manassas, Va.) using PCR primers that amplify the gene of interest. The oligonucleotides and primers referred to herein can easily be designed by a person of skill in the art based on the sequence information provided herein and in the art, and such can be synthesized by any of a number of commercial nucleotide providers, for example Retrogen, San Diego, Calif., and GENEART, Regensburg, Germany.

Plasmid Vector

Constructs of the present invention were inserted into eukaryotic expression vector V10551. This vector is built on a modified pUC18 background (see Yanisch-Perron, C., et al. Gene 33:103-119 (1985)), and contains a kanamycin resistance gene, the human cytomegalovirus immediate early 1 promoter/enhancer and intron A, and the bovine growth hormone transcription termination signal, and a polylinker for inserting foreign genes. See Hartikka, J., et al., Hum. Gene Ther. 7:1205-1217 (1996). However, other standard commercially available eukaryotic expression vectors may be used in the present invention, including, but not limited to: plasmids pcDNA3, pHCMV/Zeo, pCR3.1, pEF1/His, pIND/GS, pRc/HCMV2, pSV40/Zeo2, pTRACER-HCMV, pUB6N5-His, pVAX1, and pZeoSV2 (available from Invitrogen, San Diego, Calif.), and plasmid pCI (available from Promega, Madison, Wis.).

Plasmid DNA Purification

Plasmid DNA was transformed into Escherichia coli DH5α competent cells and highly purified covalently closed circular plasmid DNA was isolated by a modified lysis procedure (Horn, N. A., et al., Hum. Gene Ther. 6:565-573 (1995)) followed by standard double CsCl-ethidium bromide gradient ultracentrifugation (Sambrook, J., et al., Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Harbor Laboratory Press, Plainview, N.Y. (1989)). Alternatively, plasmid DNAs are purified using Giga columns from Qiagen (Valencia, Calif.) according to the kit instructions. All plasmid preparations were free of detectable chromosomal DNA, RNA and protein impurities based on gel analysis and the bicinchoninic protein assay (Pierce Chem. Co., Rockford Ill.). Endotoxin levels were measured using Limulus Amebocyte Lysate assay (LAL, Associates of Cape Cod, Falmouth, Mass.) and were less than 0.6 Endotoxin Units/mg of plasmid DNA. The spectrophotometric A₂₆₀/A₂₈₀ ratios of the DNA solutions were typically above 1.8. Plasmids were ethanol precipitated and resuspended in an appropriate solution, e.g., 150 mM sodium phosphate (for other appropriate excipients and auxiliary agents, see U.S. Patent Application Publication 20020019358, published Feb. 14, 2002). DNA was stored at −20° C. until use. DNA was diluted by mixing it with 300 mM salt solutions and by adding appropriate amount of USP water to obtain 1 mg/ml plasmid DNA in the desired salt at the desired molar concentration.

Plasmid Expression in Mammalian Cell Lines

The expression plasmids were analyzed in vitro by transfecting the plasmids into a well characterized mouse melanoma cell line (VM-92, also known as UM-449) available from the American Type Culture Collection, Manassas, Va. Other well-characterized human cell lines may also be used, e.g. MRC-5 cells, ATCC Accession No. CCL-171. The transfection was performed using cationic lipid-based transfection procedures well known to those of skill in the art. Other transfection procedures are well known in the art and may be used, for example electroporation and calcium chloride-mediated transfection (Graham F. L. and A. J. van der Eb Virology 52:456-67 (1973)). Following transfection, cell lysates and culture supernatants of transfected cells were evaluated to compare relative levels of expression of HCMV antigen proteins. The samples were assayed by western blots and ELISAs, using commercially available anti-pp65 and anti-gB monoclonal antibodies (available, e.g., from Research Diagnostics Inc., Flanders N.J.), so as to compare both the quality and the quantity of expressed antigen. Additionally, in vitro transfection assays were used to determine the effect of mixing the various plasmids comprising codon-optimized coding regions encoding HCMV pp65 and gB on levels of expression in human cells.

Expression products derived from human cells transfected with the various polynucleotide constructs were examined for molecular weight, and immunoreactive antigens (i.e., to react with HCMV antisera). In addition, a comparison of expression levels (both intra- and extra-cellular) of each class of expression plasmid (e.g., wild-type vs. human codon-optimized; truncated vs. full-length) was made.

Injections of Plasmid DNA

The quadriceps muscles of restrained awake mice (e.g., female 6-12 week old BALB/c mice from Harlan Sprague Dawley, Indianapolis, Ind.) are injected using a disposable sterile, plastic insulin syringe and 28 G ½ needle (Becton-Dickinson, Franklin Likes, N.J., Cat. No. 329430) fitted with a plastic collar cut from a micropipette tip, all as previously described (Hartikka, J., et al., Hum. Gene Ther. 7:1205-1217 (1996)). The mice are injected bilaterally in the rectus femoris muscle with 25 μg of plasmid DNA (50 μg total per mouse) formulated in a salt solution (e.g. 150 mM Sodium Phosphate or phosphate buffered saline (PBS)) or with a lipid-based delivery system.

Animal care throughout the study is in compliance with the “Guide for the Use and Care of Laboratory Animals,” Institute of Laboratory Animal Resources, Commission on Life Sciences, National Research Council, National Academy Press, Washington, D.C., 1996 as well as with Vical's Institutional Animal Care and Use Committee.

Immune Correlates

Although HCMV can only infect human cells, a number of reliable animal models for HCMV infection are known in the art, as reviewed by Staczek, and may be used with the methods of the present invention, e.g. to test immunogenicity or expression (Staczek, J. Microbiol Rev 54:247-65 (1990)). For example, the transgenic human leukocyte antigen (HLA) A*0201.Kb mouse model may be used (Gallez-Hawkins, G. et al. Scand J Immunol 55:592-8 (2002)). A mouse model of vertical HCMV transmission is described in Tang, et al., (Tang, J L, et al. Arch Virol 147:1189-95 (2002)). Several models infecting human tissue implanted onto immunodeficient SCID or nude mice have been described (Bidanset, D J, et al., J Infect Dis 184:192-5 (2001); Pari, G S, et al, J Infect Dis 177:523-8 (1998); Mocarski, E S, et al. Proc Natl Acad Sci USA 90:104-8 (1993)). Athymic rats have been used to model cytomegalovirus retinitis using HCMV (Laycock, K A, et al. Am J Ophthalmol 124:181-9 (1997)). Additionally, animal models using animal cytomegaloviruses to mimic HCMV infection have been described, including primate models in which rhesus macaques are infected with rhesus cytomegalovirus, and murine models infected with murine cytomegalovirus (Sequar, G. et al. J Viral 76:7661-71 (2002); Lockridge, K M, et al. J Viral 73:9576-83 (1999); Minamishima, Y, et al., Microbial Immunol 22:693-700 (1978)).

Example 1 Construction of an Isolated Polynucleotide Comprising a Minimally Human Codon-Optimized pp65 Coding Region, Encoding Human Cytomegalovirus pp65 with Kinase Site Deleted

VCL-6368 encodes an optimized and mutated form of the human CMV antigen pp65 cloned into the expression vector VR10551 described supra. This plasmid encodes a 557 amino acid protein (SEQ ID NO:6) in which amino acids Arg435-Lys438 of the human CMV pp65 antigen have been deleted. The coding sequence was minimally optimized for expression in humans by changing five codons that are rarely used in humans to corresponding codons that are used more frequently. The five codons and changes are: Ala GCG to GCC, Arg CGT to CGC, Pro CCG to CCC, and CCA, Ser TCG to TCC, and Thr ACG to ACC. The optimized sequence is SEQ ID NO:5.

The pp65delArg435-Lys438 insert of VCL-6368 was constructed in two steps by PCR amplification of an optimized hCMV pp65 plasmid synthesized at Retrogen Inc. (San Diego). The TOPO-hCMV-opti-pp65 plasmid (Retrogen product #8041-8081-4) was amplified with Expand DNA polymerase (Boehringer Mannheim) using the primer set T7 (Invitrogen Cat. #N650-02) (SEQ ID NO:21) and 65-delta-rev (SEQ ID NO:22) and the resulting product was gel purified as a 1330 bp fragment. An overlapping 400 bp fragment was amplified from the same parent TOPO plasmid using the primer set M13rev (Invitrogen Cat. #18430017) (SEQ ID NO:23) and 65-delta-for (SEQ ID NO:24) and the product was gel purified. Ten microliters of each of the two PCR fragments were combined in a second PCR reaction and amplified with the T7 (SEQ ID NO:21) and M13rev primer (SEQ ID NO:23) and the 1704 bp fragment was gel purified. This fragment was cut with the restriction enzymes Avr II and Nhe I and ligated with similarly digested plasmid backbone DNA. The ligation mix was transformed into E. coli (XL-2 from Stratagene, Inc.) and screened by PCR for recombinant clones using the primers VR10551FOR (SEQ ID NO:25) and hCMVpp65-R (SEQ ID NO:26). Several PCR positive clones were picked and sequenced. A minimally human codon-optimized clone encoding the correct Arg435-Lys438 deletion form of the human CMV pp65 antigen was selected and used for further analysis.

Expression of VR6368 was shown by transfection of VM92 cells and Western blot analysis using a monoclonal anti-pp65 antibody (ViroGen, lot# hCMV-pp65-4). The predicted sized protein was detected in the supernatant and cell lysate. Even though this construct encodes an intracellular protein, a significant amount ends up in the supernatant. This is not a unique or particularly unusual phenomenon.

Example 2 Construction of an Isolated Polynucleotide Comprising a Minimally Human Codon-Optimized Glycoprotein B Coding Region, Encoding the Secreted Human Cytomegalovirus Glycoprotein B

VCL-6365 encodes a secreted form of the human CMV antigen gB cloned into the expression vector VR10551 described supra. This plasmid encodes amino acids 1-713 of the human CMV gB antigen (SEQ ID NO:14). Nucleotides 1-2139 of the wild-type gB coding sequence (SEQ ID NO:11) were minimally optimized for expression in humans by changing five codons that are rarely used in humans to five corresponding codons that are used more frequently. The five codons and changes are: Ala GCG to GCC, Arg CGT to CGC, Pro CCG to CCC, CCT, and CCA, Ser TCG to TCC, and Thr ACG to ACC. The optimized sequence is SEQ ID NO:13.

VR6365 was constructed by inserting a 2160 bp synthesized fragment encoding amino acids 1-713 of the human CMV gB antigen inserted into the expression vector VR-10551. Specifically, VR-10551 was digested with the restriction enzymes Nhe I and Avr II, and the 4.5 kb linear vector was gel purified. The gB insert was obtained by digesting the minimally human codon-optimized coding region encoding the secreted gB fragment synthesized by Retrogen Inc. (San Diego, product #7981-8031(2)-1) with the restriction enzymes Nhe I and Avr II, then gel purifying the resulting 2160 bp fragment. The vector and insert fragments were ligated together, transformed into E. coli (XL-2 from Stratagene, Inc.) and screened by PCR for recombinant clones using the primers 10551F (SEQ ID NO:25) and hCMVgB-R (SEQ ID NO:27). Several PCR positive clones were sequenced. A clone with the correct nucleotide sequence and was given the designation VR6365. This clone encodes a secreted form of the human CMV antigen gB cloned into the Nhe I-Avr II sites of the expression vector VR10551.

Purified plasmid DNA was used to transfect the murine cell line VM92 to determine secretion of the minimally human-codon-optimized gB.

Secretion of the minimally human-codon-optimized gB was confirmed with an ELISA assay using plates coated with supernatants from the transfected VM92 cells. Expression and secretion was visualized with polyclonal anti-gB serum and a commercially available anti-gB monoclonal antibody (available from Research Diagnostics Inc., Flanders, N.J.).

Example 3 Construction of an Isolated Polynucleotide Comprising a Human Codon-Optimized CMV IE1 Coding Region, Encoding Human Cytomegalovirus IE1

Plasmid VCL-6520 comprises a 1236 base-pair human codon-optimized synthetic DNA construct encoding exons 2 and 4 of the human CMV IE1 gene, inserted into the expression vector VR-10551. The wild type sequence for exons 2 and 4 of the human CMV IE1 gene follows (SEQ ID NO: 50):

GAATTCGCCGCCACCATGGAGTCCTCTGCCAAGAGAAAGATGGACCCTGATAATCCTGACGAGGGCCCT TCCTCCAAGGTGCCACGGGTCAAACAGATTAAGGTTCGAGTGGACATGGTGCGGCATAGAATCAAGGAG CACATGCTGAAAAAATATACCCAGACGGAAGAGAAATTCACTGGCGCCTTTAATATGATGGGAGGATGT TTGCAGAATGCCTTAGATATCTTAGATAAGGTTCATGAGCCTTTCGAGGAGATGAAGTGTATTGGGCTA ACTATGCAGAGCATGTATGAGAACTACATTGTACCTGAGGATAAGCGGGAGATGTGGATGGCTTGTATT GATGAACTTAGGAGAAAGATGATGTATATGTGCTACAGGAATATAGAGTTCTTTACCAAGAACTCAGCC TTCCCTAAGACCACCAATGGCTGCAGTCAGGCCATGGCGGCACTGCAGAACTTGCCTCAGTGCTCCCCT GATGAGATTATGGCTTATGCCCAGAAAATATTTAAGATTTTGGATGAGGAGAGAGACAAGGTGCTCACG CACATTGATCACATATTTATGGATATCCTCACTACATGTGTGGAAACAATGTGTAATGAGTACAAGGTC ACTAGTGACGCTTGTATGATGACCATGTACGGGGGCATCTCTCTCTTAAGTGAGTTCTGTCGGGTGCTG TGCTGCTATGTCTTAGAGGAGACTAGTGTGATGCTGGCCAAGCGGCCTCTGATAACCAAGCCTGAGGTT ATCAGTGTAATGAAGCGCCGCATTGAGGAGATCTGCATGAAGGTCTTTGCCCAGTACATTCTGGGGGCC GATCCTCTGAGAGTCTGCTCTCCTAGTGTGGATGACCTACGGGCCATCGCCGAGGAGTCAGATGAGGAA GAGGCTATTGTAGCCTACACTTTGGCCACCGCTGGTGTCAGCTCCTCTGATTCTCTGGTGTCACCCCCA GAGTCCCCTGTACCCGCGACTATCCCTCTGTCCTCAGTAATTGTGGCTGAGAACAGTGATCAGGAAGAA AGTGAGCAGAGTGATGAGGAAGAGGAGGAGGGTGCTCAGGAGGAGCGGGAGGACACTGTGTCTGTCAAG TCTGAGCCAGTGTCTGAGATAGAGGAAGTTGCCCCAGAGGAAGAGGAGGATGGTGCTGAGGAACCCACC GCCTCTGGAGGCAAGAGCACCCACCCTATGGTGACTAGAAGCAAGGCTGACCAGTGAGGATCC

The insert in the VCL-6250 construct was synthesized by GENEART www_geneart_de/, Regensburg, Germany). VCL-6250 has the following sequence (SEQ ID NO:28):

10ATATCGCCGCCACCATGGAGTCTAGCGCCAAGAGGAAGATGGACCCCGACAACCCTGATGAGGGCC CTAGCAGCAAGGTGCCCCGGGTGAAGCAGATCAAGGTGCGGGTGGACATGGTGCGGCACAGGATCAAG GAACACATGCTGAAGAAGTACACCCAGACCGAGGAGAAGTTCACCGGCGCCTTCAATATGATGGGCGG CTGCCTGCAGAATGCCCTGGACATCCTGGACAAGGTGCACGAGCCCTTCGAGGAGATGAAGTGCATCG GCCTGACCATGCAGAGCATGTACGAGAACTACATCGTGCCCGAGGACAAGAGGGAGATGTGGATGGCC TGCATCGACGAGCTGCGGCGGAAGATGATGTACATGTGCTACCGGAACATCGAGTTCTTCACCAAGAA CAGCGCCTTCCCCAAGACCACCAACGGATGCTCTCAGGCCATGGCCGCCCTGCAGAATCTGCCTCAGT GCAGCCCCGATGAGATCATGGCCTACGCCCAGAAGATCTTCAAGATCCTGGACGAGGAGAGGGATAAG GTGCTGACCCACATCGACCACATCTTCATGGACATCCTGACCACCTGCGTGGAGACCATGTGCAACGA GTACAAGGTGACCAGCGACGCCTGCATGATGACAATGTACGGCGGCATCAGCCTGCTGAGCGAGTTCT GCAGAGTGCTGTGCTGCTACGTGCTGGAGGAGACCTCTGTGATGCTGGCCAAGAGGCCCCTGATCACC AAGCCTGAGGTGATCAGCGTGATGAAGCGGCGGATCGAGGAGATCTGCATGAAGGTGTTCGCCCAGTA CATCCTGGGAGCCGACCCTCTGAGAGTGTGTAGCCCCAGCGTGGATGACCTGAGAGCCATCGCCGAGG AATCTGATGAAGAGGAGGCCATCGTGGCCTATACACTGGCCACAGCCGGCGTGTCTAGCAGCGATAGC CTGGTGAGCCCTCCTGAGTCTCCTGTGCCTGCCACAATCCCTCTGAGCAGCGTGATCGTGGCCGAGAA CAGCGATCAGGAGGAGAGCGAGCAGTCTGATGAGGAAGAGGAAGAGGGAGCCCAGGAGGAGAGAGAGG ATACCGTGAGCGTGAAGAGCGAGCCTGTGAGCGAGATCGAAGAGGTGGCCCCTGAGGAAGAAGAGGAT GGCGCCGAGGAGCCTACAGCCAGCGGCGGCAAGTCAACACACCCCATGGTGACCAGAAGCAAGGCCGA CCAGTAAGGATCC

VCL-6250 was constructed by isolating the EcoR5-BamHI IE1 synthetic insert and ligating it into the expression vector VR-10551, described above. Specifically, VR-10551 was digested with restriction enzymes and gel purified, as described in the preceding examples. The vector and insert fragments were ligated together, transformed into E. coli DH10B cells (available, e.g., from Invitrogen). Selected recombinant plasmids were completely sequences using the primers synthesized according to the following table:

TABLE 9 Primers Primer Sequence SEQ ID NO 2944S CTG CGC CTT ATC CGG TAA CT SEQ ID NO: 33 5876 CAG TGA GGC ACC TAT CTC AG SEQ ID NO: 34 5760 CAC CAT GAG TGA CGA CTG AA SEQ ID NO: 35 5761 TTA ATC GCG GCC TCG AGC AA SEQ ID NO: 36 5762 GGC TCA TGT CCA ACA TTA CC SEQ ID NO: 37 931S GAG ACG CCA TCC ACG CTG TT SEQ ID NO: 38 5874 CAG ACT TAG GCA CAG CAC AA SEQ ID NO: 39 5104 GAG CGA GGA AGC GGA AGA GT SEQ ID NO: 40 3054A CCG CCT ACA TAC CTC GCT CT SEQ ID NO: 41 5767 GAG CAT TAC GCT GAC TTG AC SEQ ID NO: 42 5768 ATG CCT CTT CCG ACC ATC AA SEQ ID NO: 43 5770 GGC GGT AAT GTT GGA CAT GA SEQ ID NO: 44 847A GGC GGA GTT GTT ACG ACA TT SEQ ID NO: 45 5772 CAT TGT GCT GTG CCT AAG TC SEQ ID NO: 46 GA seqF1 CCA GAC CGA GGA GAA GTT CA SEQ ID NO: 47 GA seqF2 TGC TGG AGG AGA CCT CTG TG SEQ ID NO: 48 GA seqR2 TCG ATC CGC CGC TFC ATC AC SEQ ID NO: 49

Purified VCL-6250 DNA was used to transfect the murine cell line VM92 to determine expression of the IE1 protein. Expression of IE1 was confirmed with a Western Blot assay. Expression was visualized with a commercially available anti-IE1 monoclonal antibody (available from Chemicon International, Temecula, Calif.).

Example 4 Preparation of Vaccine Formulations

In each of the following methods, HCMV antigen-encoding plasmids of the present invention are formulated with the poloxamer system, described herein as VF-P1205-02A. VF-P1205-02A refers to a poloxamer-based delivery system consisting of the non-ionic block copolymer, CRL 1005, and a cationic surfactant, BAK (Benzalkonium chloride 50% solution, available from Ruger Chemical Co. Inc.). Specific final concentrations of each component of the formulae are described in the following methods, but for any of these methods, the concentrations of each component may be varied by basic stoichiometric calculations known by those of ordinary skill in the art to make a final solution having the desired concentrations.

For example, the concentration of CRL 1005 is adjusted depending on, for example, transfection efficiency, expression efficiency, or immunogenicity, to achieve a final concentration of between about 1 mg/ml to about 75 mg/ml, for example, about 1 mg/ml, about 2 mg/ml, about 3 mg/ml, about 4 mg/ml, about 5 mg/ml, about 6.5 mg/ml, about 7 mg/ml, about 7.5 mg/ml, about 8 mg/ml, about 9 mg/ml, about 10 mg/ml, about 15 mg/ml, about 20 mg/ml, about 25 mg/ml, about 30 mg/ml, about 35 mg/ml, about 40 mg/ml, about 45 mg/ml, about 50 mg/ml, about 55 mg/ml, about 60 mg/ml, about 65 mg/ml, about 70 mg/ml, or about 75 mg/ml of CRL 1005.

Similarly the concentration of DNA is adjusted depending on many factors, including the amount of a formulation to be delivered, the age and weight of the subject, the delivery method and route and the immunogenicity of the antigen being delivered. In general, formulations of the present invention are adjusted have a final concentration from about 1 ng/ml to about 30 mg/ml of plasmid (or other polynucleotide). For example, a formulation of the present invention may have a final concentration of about 1 ng/ml, about 5 ng/ml, about 10 ng/ml, about 50 ng/ml, about 100 ng/ml, about 500 ng/ml, about 1 μg/ml, about 5 μg/ml, about 10 μg/ml, about 50 μg/ml, about 200 μg/ml, about 400 μg/ml, about 600 μg/ml, about 800 μg/ml, about 1 mg/ml, about 2 mg/ml, about 2.5, about 3 mg/ml, about 3.5, about 4 mg/ml, about 4.5, about 5 mg/ml, about 5.5 mg/ml, about 6 mg/ml, about 7 mg/ml, about 8 mg/ml, about 9 mg/ml, about 10 mg/ml, about 20 mg/ml, or about 30 mg mg/ml of a plasmid.

Certain formulations of the present invention include a cocktail of plasmids, for example, a mixture of two or more of plasmids VCL-6365, VCL-6368, or VCL-6520 of the present invention, and optionally plasmids comprising codon-optimized or non-codon-optimized coding regions encoding other HCMV antigens, e.g., an antigenic portion if HCMV IE1, and/or plasmids encoding immunity enhancing proteins, e.g., cytokines. Various plasmids desired in a cocktail are combined together in PBS or other diluent prior to the addition to the other ingredients. Furthermore, plasmids may be present in a cocktail at equal proportions, or the ratios may be adjusted based on, for example, relative expression levels of the antigens or the relative immunogenicity of the encoded antigens. Thus, various plasmids in the cocktail may be present in equal proportion, or up to twice or three times, or more, as much of one plasmid may be included relative to other plasmids in the cocktail.

Additionally, the concentration of BAK may be adjusted depending on, for example, a desired particle size and improved stability: Indeed, in certain embodiments, formulations of the present invention include CRL 1005 and DNA, but are free of BAK. In general BAK-containing formulations of the present invention are adjusted to have a final concentration of BAK from about 0.05 mM to about 0.5 mM. For example, a formulation of the present invention may have a final BAK concentration of about 0.05 mM, 0.1 mM, 0.2 mM, 0.3 mM, 0.4 mM, or 0.5 mM.

The total volume of the formulations produced by the methods below may be scaled up or down, by choosing apparatus of proportional size. Finally, in carrying out any of the methods described below, the three components of the formulation, BAK, CRL 1005, and plasmid DNA, may be added in any order. In each of these methods described below the term “cloud point” refers to the point in a temperature shift, or other titration, at which a clear solution becomes cloudy, i.e., when a component dissolved in a solution begins to precipitate out of solution.

A. Thermal Cycling of a Pre-Mixed Formulation

This example describes the preparation of a formulation comprising 0.3 mM BAK, 7.5 mg/ml CRL 1005, and 5 mg/ml of DNA in a total volume of 3.6 ml. The ingredients are combined together at a temperature below the cloud point and then the formulation is thermally cycled to room temperature (above the cloud point) several times, according to the protocol outlined in FIG. 8.

A 1.28 mM solution of BAK is prepared in PBS, 846 μl of the solution is placed into a 15 ml round bottom flask fitted with a magnetic stirring bar, and the solution is stirred with moderate speed, in an ice bath on top of a stirrer/hotplate (hotplate off) for 10 minutes. CRL 1005 (27 μl) is then added using a 100 μl positive displacement pipette and the solution is stirred for a further 60 minutes on ice. Plasmids VCL-6365 and VCL-6368, and optionally, additional plasmids encoding, e.g., additional HCMV antigens, e.g., VLC-6520, are mixed together at desired proportions in PBS. In the present example, 2.73 ml of a solution containing 3.2 mg/ml VCL-6365 and 3.2 mg/ml VCL-6368 (6.4 mg/ml total DNA) is added drop wise, slowly, to the stirring solution over 1 min using a 5 ml pipette. The solution at this point (on ice) is clear since it is below the cloud point of the poloxamer and is further stirred on ice for 15 min. The ice bath is then removed, and the solution is stirred at ambient temperature for 15 minutes to produce a cloudy solution as the poloxamer passes through the cloud point.

The flask is then placed back into the ice bath and stirred for a further 15 minutes to produce a clear solution as the mixture is cooled below the poloxamer cloud point. The ice bath is again removed and the solution stirred at ambient temperature for a further 15 minutes. Stirring for 15 minutes above and below the cloud point (total of 30 minutes), is defined as one thermal cycle. The mixture is cycled six more times. The resulting formulation may be used immediately, or may be placed in a glass vial, cooled below the cloud point, and frozen at −80° C. for use at a later time.

B. Thermal Cycling, Dilution and Filtration of a Pre-Mixed Formulation, Using Increased Concentrations of CRL 1005

This example describes the preparation of a formulation comprising 0.3 mM BAK, 34 mg/ml or 50 mg/ml CRL 1005, and 2.5 mg/ml of DNA in a final volume of 4.0 ml. The ingredients are combined together at a temperature below the cloud point, then the formulation is thermally cycled to room temperature (above the cloud point) several times, diluted, and filtered according to the protocol outlined in FIG. 9.

Plasmids VCL-6365 and VCL-6368, and optionally, additional plasmids encoding, e.g., additional HCMV antigens, e.g., VLC-6520, are mixed together at desired proportions in PBS. For the formulation containing 34 mg/ml CRL 1005, 1.55 ml of a solution containing about 3.2 mg/ml VCL-6365 and about 3.2 mg/ml VCL-6368 (about 6.4 mg/ml total DNA) is placed into the 15 ml round bottom flask fitted with a magnetic stirring bar, and for the formulation containing 50 mg/ml CRL 1005, 1.52 ml of a solution containing about 3.2 mg/ml VCL-6365 and about 3.2 mg/ml VCL-6368 (about 6.4 mg/ml total DNA) is placed into the 15 ml round bottom flask fitted with a magnetic stirring bar, and the solutions are stirred with moderate speed, in an ice bath on top of a stirrer/hotplate (hotplate off) for 10 minutes. CRL 1005 (68 μl for 34 mg/ml final concentration, and 100 μl for 50 mg/ml final concentration) is then added using a 100 μl positive displacement pipette and the solution is stirred for a further 30 minutes on ice. A 1.6 mM solution of BAK is prepared in PBS, and 375 μl is then added drop wise, slowly, to the stirring 34 mg/ml or 50 mg/ml mixtures, over 1 min using a 1 ml pipette. The solutions at this point are clear since they are below the cloud point of the poloxamer and are stirred on ice for 30 min. The ice baths are then removed; the solutions stirred at ambient temperature for 15 minutes to produce cloudy solutions as the poloxamer passes through the cloud point.

The flasks are then placed back into the ice baths and stirred for a further 15 minutes to produce clear solutions as the mixtures cooled below the poloxamer cloud point. The ice baths are again removed and the solutions stirred for a further 15 minutes. Stirring for 15 minutes above and below the cloud point (total of 30 minutes), is defined as one thermal cycle. The mixtures are cycled two more times.

In the meantime, two Steriflip® 50 ml disposable vacuum filtration devices, each with a 0.22 μm Millipore Express® membrane (available from Millipore, cat #SCGP00525) are placed in an ice bucket, with a vacuum line attached and left for 1 hour to allow the devices to equilibrate to the temperature of the ice. The poloxamer formulations are then diluted to 2.5 mg/ml DNA with PBS and filtered under vacuum.

The resulting formulations may be used immediately, or may be transferred to glass vials, cooled below the cloud point, and frozen at −80° C. for use at a later time.

C. A Simplified Method without Thermal Cycling

This example describes a simplified preparation of a formulation comprising 0.3 mM BAK, 7.5 mg/ml CRL 1005, and 5 mg/ml of DNA in a total volume of 3.6 ml. The ingredients are combined together at a temperature below the cloud point and then the formulation is simply filtered and then used or stored, according to the protocol outlined in FIG. 10.

A 0.77 mM solution of BAK is prepared in PBS, and 780 μl of the solution is placed into a 15 ml round bottom flask fitted with a magnetic stirring bar, and the solution is stirred with moderate speed, in an ice bath on top of a stirrer/hotplate (hotplate off) for 15 minutes. CRL 1005 (15 μl) is then added using a 100 μl positive displacement pipette and the solution is stirred for a further 60 minutes on ice. Plasmids VCL-6365 and VCL-6368, and optionally, additional plasmids encoding, e.g., additional HCMV antigens, e.g., VLC-6250, are mixed together at desired proportions in PBS. In the present example, about 1.2 ml of a solution containing about 4.1 mg/ml VCL-6365 and about 4.2 mg/ml VCL-6368 (about 8.3 mg/ml total DNA) is added drop wise, slowly, to the stirring solution over 1 min using a 5 ml pipette. The solution at this point (on ice) is clear since it is below the cloud point of the poloxamer and is further stirred on ice for 15 min.

In the meantime, two Steriflip® 50 ml disposable vacuum filtration devices, each with a 0.22 μm Millipore Express® membrane (available from Millipore, cat #SCGP00525) are placed in an ice bucket, with a vacuum line attached and left for 1 hour to allow the devices to equilibrate to the temperature of the ice. The poloxamer formulation was then filtered under vacuum, below the cloud point and then allowed to warm above the cloud point. The resulting formulations may be used immediately, or may be transferred to glass vials, cooled below the cloud point and then frozen at −80° C. for use at a later time.

Example 5 Animal Immunization

The immunogenicity of expression products encoded by one or more of the codon-optimized polynucleotides described in Examples 1, 2 and 3, and optionally the codon-optimized polynucleotides described in Example 4, are evaluated based on each plasmid's ability to mount an immune response in vivo. Plasmids are tested individually and in combinations by injecting single constructs as well as multiple constructs. Immunizations are initially carried out in animals, such as mice, rabbits, goats, sheep, primates, or other suitable animal, by intramuscular (IM) injections. Serum is collected from immunized animals, and the immune response is quantitated. The tests of immunogenicity further include measuring antibody titer, neutralizing antibody titer, T cell cytokine production and T cell cytolytic activity. Correlation to protective levels in humans are made according to methods well known by those of ordinary skill in the art. See “immune correlates,” above.

A. DNA Formulations

Plasmid DNA is formulated by any of the methods described in Example 4. Alternatively, plasmid DNA is prepared as described above and dissolved at a concentration of about 0.1 mg/ml to about 10 mg/ml, preferably about 1 mg/ml, in PBS with or without transfection-facilitating cationic lipids, e.g., DMRIE/DOPE at a 4:1 DNA:lipid mass ratio. Alternative DNA formulations include 150 mM sodium phosphate instead of PBS, adjuvants, e.g., Vaxfectin™ at a 4:1 DNA:Vaxfectin™ mass ratio, mono-phosphoryl lipid A (detoxified endotoxin) from S. minnesota (MPL) and trehalosedicorynomycolateAF (TDM), in 2% oil (squalene)-Tween 80-water (MPL+TDM, available from Sigma/Aldrich, St. Louis, Mo., (catalog #M6536)), a solubilized mono-phosphoryl lipid A formulation (AF, available from Corixa), or (±)-N-(3-Acetoxypropyl)-N,N-dimethyl-2,3-bis(octyloxy)-1-propanaminium chloride (compound # VC1240) (see Shriver, J. W. et al., Nature 415:331-335 (2002), and P.C.T. Publication No. WO 02/00844 A2, each of which is incorporated herein by reference in its entirety).

B. Animal Immunizations

Codon-optimized and wild type DNA plasmids encoding secreted gB and pp65, and their respective mutant variants, as described above, are injected into BALB/c mice as single plasmids, as either DNA in PBS or formulated with the poloxamer-based delivery system: 3 mg/ml DNA, 34 or 50 mg/ml CRL 1005, and 0.3 mM BAK. Groups of 10 mice are immunized three times, at biweekly intervals, and serum is obtained to determine antibody titers to each of the antigens. Groups are also included in which mice are immunized with a trivalent preparation, containing each of the three plasmids in equal mass. The study design for each plasmid is shown in Table 10, and a typical immunization protocol is shown in Table 11.

TABLE 10 Study Design for Plasmids Group Number of animals DNA in PBS 10 DNA formulated with CRL 1005 and BAK 10 Plasmid backbone (VR10551), DNA in PBS 5

TABLE 11 Immunization Schedule Day Immunization −3 Pre-bleed 0 Plasmid injections, intramuscular, bilateral in rectus femoris, 25 μg/leg 14 Plasmid injections, intramuscular, bilateral in rectus femoris, 25 μg/leg 20 Serum collection 28 Plasmid injections, intramuscular, bilateral in rectus femoris, 25 μg/leg 35 Serum collection

Serum antibody titers are determined by ELISA with recombinant proteins or transfection supernatants and lysates from transfected VM-92 cells or virus-infected cell lysates.

C. Production of HCMV pp65 and gB Antisera in Animals

Plasmid DNA encoding HCMV pp65, gB, IE1 or fragments, variants or derivatives thereof is prepared according to the immunization scheme described above and injected into a suitable animal for generating polyclonal antibodies. Serum is collected and the antibody titered as above. The titer of anti-HCMV peptide antibodies in serum from immunized animals may be increased by selection of anti-peptide antibodies, for instance, by adsorption to the peptide on a solid support and elution of the selected antibodies according to methods well known in the art.

Monoclonal antibodies are also produced using hybridoma technology (Kohler, et al., Nature 256:495 (1975); Kohler, et al., Eur. J. Immunol. 6:511 (1976); Kohler, et al, Eur. J. Immunol. 6:292 (1976); Hammerling, et al., in Monoclonal Antibodies and T-Cell Hybridomas, Elsevier, N.Y., (1981), pp. 563-681, each of which is incorporated herein by reference in its entirety). In general, such procedures involve immunizing an animal (preferably a mouse) as described above. Suitable cells can be recognized by their capacity to bind anti-HCMV pp65, gB antibody or IE1 antibody. Such cells may be cultured in any suitable tissue culture medium; however, it is preferable to culture cells in Earle's modified Eagle's medium supplemented with 10% fetal bovine serum (inactivated at about 56° C.), and supplemented with about 10 g/1 of nonessential amino acids, about 1,000 U/ml of penicillin, and about 100 g/ml of streptomycin. The splenocytes of such mice are extracted and fused with a suitable myeloma cell line. Any suitable myeloma cell line may be employed in accordance with the present invention; however, it is preferable to employ the parent myeloma cell line (SP2/0), available from the American Type Culture Collection, Rockville, Md. After fusion, the resulting hybridoma cells are selectively maintained in HAT medium, and then cloned by limiting dilution as described by Wands et al., Gastroenterology 80:225-232 (1981), incorporated herein by reference in its entirety. The hybridoma cells obtained through such a selection are then assayed to identify clones which secrete antibodies capable of binding HCMV pp65 or gB.

Alternatively, additional antibodies capable of binding to HCMV pp65 or gB may be produced in a two-step procedure through the use of anti-idiotypic antibodies. Such a method makes use of the fact that antibodies are themselves antigens, and that, therefore, it is possible to obtain an antibody which binds to a second antibody. In accordance with this method, HCMV pp65 or gB specific antibodies are used to immunize an animal, preferably a mouse. The splenocytes of such an animal are then used to produce hybridoma cells, and the hybridoma cells are screened to identify clones which produce an antibody whose ability to bind to the HCMV protein-specific antibody can be blocked by HCMV pp65 or gB. Such antibodies comprise anti-idiotypic antibodies to the HCMV protein-specific antibody and can be used to immunize an animal to induce formation of further HCMV pp65 or gB-specific antibodies.

It will be appreciated that Fab and F(ab′)2 and other fragments of the antibodies of the present invention may be used according to the methods disclosed herein. Such fragments are typically produced by proteolytic cleavage, using enzymes such as papain (to produce Fab fragments) or pepsin (to produce F(ab′)2 fragments). Alternatively, HCMV pp65 or gB-binding fragments can be produced through the application of recombinant DNA technology or through synthetic chemistry.

It may be preferable to use “humanized” chimeric monoclonal antibodies. Such antibodies can be produced using genetic constructs derived from hybridoma cells producing the monoclonal antibodies described above. Methods for producing chimeric antibodies are known in the art. See, for review, Morrison, Science 229:1202 (1985); Oi, et al., BioTechniques 4:214 (1986); Cabilly, et al., U.S. Pat. No. 4,816,567; Taniguchi, et al., EP 171496; Morrison, et al., EP 173494; Neuberger, et al., WO 8601533; Robinson, et al., WO 8702671; Boulianne, et al., Nature 312:643 (1984); Neuberger, et al., Nature 314:268 (1985).

These antibodies are used, for example, in diagnostic assays, as a research reagent, or to further immunize animals to generate HCMV-specific anti-idiotypic antibodies. Non-limiting examples of uses for anti-HCMV antibodies include use in Western blots, ELISA (competitive, sandwich, and direct), immunofluorescence, immunoelectron microscopy, radioimmunoassay, immunoprecipitation, agglutinatione assays, immunodiffisuon, immunoelectrophoresis, and epitope mapping (Weir, D. Ed. Handbook of Experimental Immunology, 4^(th) ed. Vols. I and II, Blackwell Scientific Publications (1986)).

Example 6 Quantitative, Real Time RT-PCR Analysis of mRNA Expression of Constructs Encoding HCMV pp65 and gB, and Fragments, Variants and Derivatives Thereof

Quantitation of the mRNA levels expressed from the HCMV pp65, gB and IE1 constructs is a valuable biological marker for gene activity. Various methods can be used to measure the levels of mRNA, such as Northern blots, slot blots, and other techniques known to those skilled in the art. However, a rapid method based on real-time RT-PCR provides an efficient, reliable means to monitor gene activity. One such system is the TaqMan® RT-PCR assay used with an ABI PRISM® Sequence Detection System, both available from Applied Biosystems, Inc. (Foster City, Calif.).

Briefly, RNA is extracted using conventional or commercially available techniques. After extraction, the RNA is aliquotted into optically transparent tubes or wells of a microtiter plate containing the provided buffers, enzymes, and reagents supplied with the appropriate kit, e.g., TaqMan® Gold RT-PCR Kit (Applied Biosystems, Inc., Foster City, Calif.). Additionally, the construct specific primers and probe, which can be designed by a person skilled in the art based on the sequences described herein, or commercially, e.g., ABI PRISM®. Primers & TaqMan® Probes Synthesis Service (Applied Biosystems, Inc., Foster City, Calif.) are added. The samples are placed in the ABI PRISM® Sequence Detection System, a thermocycler coupled to a laser capable of exciting the fluorophores present on the probe and a suitable detection system. Initially, the RNA is reverse transcribed into DNA, then thermostable DNA polymerase and sequence-specific primers contained in the reaction solution initiate the temperature-controlled amplification cycles. The probe used for detection of the amplification product is labeled with a low energy fluorophore (the reporter) and a high energy fluorophore (the quencher), which prevents emissions of the reporter from being detected if the quencher is closely associated with the reporter through fluorescence resonance energy transfer (FRET). At the beginning of the reaction cycle, the probe is in excess, so the majority remains unhybrized and intact, resulting in no signal. However, as the DNA product accumulates, a higher proportion of the probe is bound to the DNA. The bound probe is then degraded by the 5′ nuclease activity of the DNA polymerase used for the amplification, which releases the reporter from the quencher and creates a detectable signal. As the PCR reaction progresses and the amplified product accumulates, more of the probe is degraded, inducing a greater signal that is recorded. The number of amplification cycles necessary to detect a signal (Ct) is directly proportional to the amount of starting template, or construct mRNA. By comparing Ct values between the sample and controls starting with a known amount of RNA, it is possible to quantitate the amount of mRNA expressed in cells transfected with plasmids containing the HCMV constructs. See the Applied Biosystem, Inc. tutorial “Real-Time PCR Vs. Traditional PCR” on the world wide web www_appliedbiosystems_com/support/tutorials/, visited Nov. 15, 2002. Other real time detection systems include “Molecular Beacon” probes, see, e.g., U.S. Pat. No. 6,103,476 to Kramer and Tyagi, which is incorporated herein by reference.

For the in vitro studies, suitable cells are seeded into 24 well tissue culture plates. Once the cells are at an appropriate cell density, plasmid DNA containing codon-optimized and non-codon-optimized HCMV constructs or appropriate controls, e.g. negative controls containing the plasmid backbone with no HCMV construct, is used to transfect the cells. At various time-points post-transfection, the cells are collected for RNA extraction, for example with 4M guanidinium thiocyanate followed by phenol extraction. Cells collected from in vivo studies are also used for RNA extraction. The extracted total RNA is quantitated by measuring the absorbance of the sample at 260 nm, diluted according to the Taqman® kit instructions (Applied Biosystems, Inc., Foster City, Calif.), and aliquotted into 386 well plates suitable for real-time PCR containing the buffers, nucleotides, and enzymes necessary. Controls containing known amounts of starting RNA are included in the assay, and optionally an internal standard may be included in the samples for quality assurance. This internal standard is typically an unrelated gene product, usually an abundant endogenous RNA. Primers and probes specific for the construct and optionally internal standard are also included. The primers are designed and synthesized in the same manner as conventional PCR primers, which is a routine task for one of skill in the art. To ensure reproducibility and specificity, multiple primer sets are used in the reaction, each targeting different regions of the construct. The primer is synthesized in a similar manner, but the fluorophores, e.g. FAM and TAMRA, are covalently attached by conventional methods. The reaction proceeds as described above, and the resulting Ct values of the samples are compared to those of the controls. Starting quantities of the mRNA are interpolated using the control Ct values.

After mRNA quantitation, the mRNA level is correlated with protein expression, both intracellular and secreted. Supernatant is collected from the tissue culture medium (or from the supernatant of centrifuged cells collected in vivo) at various time-points post-transfection. Additionally, a suitable number of cells are retained after harvesting for use in protein extraction. Western blots, slot blots, ELISA and other protein quantitation techniques are used to measure the HCMV protein levels produced by the transfected cells.

Example 7 Demonstration of Immunogenicity Plasmids Encoding Human CMV Antigens

General Experimental Procedure

The experimental procedure for the following example is as described above, with particular parameters and materials employed as described herein.

Plasmids

As described above, constructs of the present invention were inserted into the expression vector VR10551.

VR10551 is an expression vector without any transgene insert (backbone for the HCMV plasmids).

VR6365 contains the coding sequence for a secreted version of human CMV gB (amino acids 1-713) cloned into the VR10551 expression vector (Example 1). The DNA was prepared using Qiagen plasmid purification kits, and was characterized and formulated with the VF-P1205-02A poloxamer-based delivery system.

VR6368 contains the coding sequence of the full-length HCMV pp65, deleted of residues ⁴³⁵RKRK⁴³⁸ in the putative kinase domain, cloned into the VR10551 expression vector (Example 2). The DNA was prepared using Qiagen plasmid purification kits, and was characterized and formulated with the VF-P1205-02A poloxamer-based delivery system, as above.

Poloxamer Formulation

The VF-P1205-02A poloxamer-based delivery system was formulated using a protocol equivalent to Example 4B, with an initial DNA, poloxamer and BAK concentration of 5.0 mg/ml, 7.5 mg/ml and 0.3 mM, respectively. Formulations were diluted with PBS at room temperature to the required experimental concentrations prior to injection.

Vaccination Regimen

Groups of nine, 6- to 8-week old female BALB/c mice (Harlan-Sprague-Dawley) received intramuscular (rectus femoris) injections containing 100 μg of pp65 DNA, 100 μg of gB DNA, or 100 μg each of pp65 and gB DNA delivered with PBS or the CRL 1005 poloxamer formulation described above. Control mice received 100 μg of pp65 DNA or 100 μg of gB DNA mixed with 100 μg of non-coding, vector DNA (VR10551) delivered with PBS or VF-P1205-02A. All mice received two vaccinations (administered on days 0 and 13) containing a total of 200 μg of DNA, 100 μg pp65 DNA and the 100 μg gB DNA. Sera were collected after the first (day 11) and second (day 22) vaccinations, and gB- and pp65-specific antibody responses were measured by ELISA and immunoblot analysis, respectively.

Recombinant gB Enzyme Linked Immunosorbent Assay (ELISA)

Sera were collected from the mice vaccinated according to the regimen described above. Anti-gB IgG titers were determined using a recombinant CMV gB Enzyme Linked Immunosorbent Assay (ELISA).

Ninety six-well, half area, high-binding EIA (Enzyme ImmunoAssay) plates were coated with recombinant CMV gB at a concentration of 0.05 μg/well (50 μL/well) in Borate Buffered Saline (BBS) buffer at 4° C. overnight. Plates were covered with an adhesive plate sealer for all incubations. After coating, plates were blotted on paper towels and 100 μL of blocking buffer (0.1% [w/v] BSA in BBS) was added to each well. Sealed plates were incubated at room temperature for 2 hours and were then stored at 4° C. until sera had been diluted. Sera were diluted in 0.5% (w/v) BSA in BBS in Eppendorf tubes, and were mixed by inversion and brief vortexing. Blocked plates were blotted and 100 μL of diluted serum was added to each well. Plates were sealed and incubated overnight at 4° C. Plates were then washed on a four wash cycle on an automated plate washer with 0.1% (v/v) Tween-20 in BBS and were blotted on paper towels. Alkaline phosphate labeled anti-mouse IgG Fc secondary antibody was diluted 1:2000 in 0.5% (w/v) BSA in BBS and 80 μL of diluted secondary antibody was added to each well. Plates were sealed and were incubated at room temperature for 2 hours. Plates were washed again on the four wash cycle on the automated plate washer and were blotted on paper towels. Fifty microliters of developing solution (1 mg/ml para-nitrophenyl phosphate in 50 mM sodium bicarbonate buffer, pH 9.8 and 1 mM MgCl₂) was added to each well, plates were sealed and incubated at room temperature. Absorbance at 405 nm, A₄₀₅, (single wavelength) was read on the plate reader. Titers were determined as the dilution at which the mean absorbance value of the immune serum was at least twice that of the mean absorbance value for the pre-immune serum at a dilution of 1:100.

Immunoblots to Detect pp65

Lysates from murine melanoma VM92 cells transfected with either VR6368 or VR10551 were made directly in 1× NuPAGE LDS sample buffer and were stored at −80° C. until needed. After thawing at room temperature, one tenth of the sample volume of 0.5 MM dithiothreitol was added to each sample. Samples were then heated at 85° C. for 10 min and were cooled immediately on ice prior to loading on NuPAGE 4-12% Bis-Tris gels. Electrophoresis was carried out at 200 V for 60 minutes at room temperature. For transfer of proteins, polyvinylidene difluoride (PVDF) membranes were first soaked in methanol for 30 s and then equilibrated in 1× NuPAGE transfer buffer containing 20% (v/v) methanol. Proteins were transferred from gels to PVDF membranes at 30V for 60 min at room temperature. After protein transfer, membranes were rinsed in milli-Q water and then blocked for 45 min at room temperature in 1% (w/v) BSA in BBS on an orbital shaker. After blocking, membranes were stored at 4° C. in 1% (w/v) BSA in BBS for no longer than 24 hr. Blots were cut into strips and were incubated in mouse immune serum diluted in 0.5% (w/v) BSA in BBS at room temperature overnight on an orbital shaker. After washing in BBS, the strips were incubated in secondary antibody (goat anti-mouse IgG Fcγ conjugated to alkaline phosphatase) at room temperature for 2.5 hr. Strips were then washed again in BBS and were developed in alkaline phosphatase substrate solution for 10 min at room temperature. Strips were then rinsed thoroughly in distilled water and were allowed to dry at room temperature between paper towels.

Mice were vaccinated with gB plasmid (VR6365) or gB/pp65 plasmid combination, as described above. The anti-gB IgG titers, measured after two vaccinations in mice vaccinated with gB plasmid (VR6365), alone or in combination with pp65 plasmid (VR6368) are given below:

TABLE 12 Anti-gB IgG Titers Following 2^(nd) Vaccination mean reciprocal titer geometric mean Group (range) reciprocal titer gB 42,667 34,836 (poloxamer formulation) (12,800-102,400) Combination 17,244 13,825 (poloxamer formulation) (1,600-25,600) gB 29,867 27,650 (naked DNA) (12,800-51,200)  Combination 10,667 8,709 (naked DNA) (3,200-25,600)

All mice vaccinated with plasmid DNA encoding HCMV gB alone or in combination, either with or without VF-P1205-02A, had detectable anti-gB IgG titers after two injections of DNA. Sera from mice injected with pp65 DNA only were pooled and tested. The binding activity for the pp65 only group was the same as for the pre-bleed sera, indicating that gB specific antibodies were not detected.

pp65 Immunoblots

Mouse sera collected after the second DNA vaccination were tested on immunoblots of lysates from cells transfected with pp65 plasmid (VR6368) as described above to determine, qualitatively, the difference in the antibody responses to pp65 in mice vaccinated with VR6368 alone and mice vaccinated with the plasmid combination. In the first set of immunoblots, pooled sera from each group of mice vaccinated with VR6368 were tested at dilutions of 1:200, 1:400, 1:800, 1:1000 and 1:2000. A sample of pooled sera from mice vaccinated with VR6365 (gB) formulated in VF-P1205-02A was included as a negative control. A pp65-specific murine monoclonal antibody was included as a positive control. Each immunoblot strip had a lane of molecular weight standards, a lane containing VR6368-transfected cell lysate, and a VR10551 transfected cell lysate control lane. All mice (nine of nine) vaccinated with pp65 DNA formulated with VF-P1205-02A had detectable antibody to pp65 by immunoblot when sera were tested at dilution of 1:200. Six of nine mice vaccinated with the bivalent HCMV plasmid vaccine formulated with VF-P1205-02A had detectable antibody to pp65 by immunoblot when tested at a dilution of 1:200. Immunoblot titration of pooled sera from the mice vaccinated with either the pp65 DNA formulated with VF-P1205-02A, or the bivalent HCMV plasmid vaccine formulated with VF-P1205-02A did not reveal a marked difference in the antibody response to pp65 between the groups. No pp65 antibody was detected in mice vaccinated with gB DNA alone.

Thus, plasmids VR6365 (gB) and VR6368 (pp65) elicited the production of antigen-specific antibodies in mice that received two injections of the plasmids either alone or in combination. Although we cannot quantify the anti-pp65 antibody response using immunoblots, they do show that the majority of mice had a detectable antibody response to pp65, and that the combination of the two plasmids did not result in complete suppression of the response to pp65. Antibody responses to pp65 in this study served as an additional readout for confirmation of production of this protein in vivo after vaccination with VR6368.

pp65-Specific IFN-γ ELISpot Assay

T cell responses to the DNA-encoded pp65 were determined by IFN-γ ELISpot assay. Splenocytes of vaccinated mice were stimulated with two separate pools of overlapping peptides, that, together, span the entire pp65 protein and should contain all possible T cell epitopes. Therefore, the type of the T cell (e.g., CD8⁺ or CD4⁺) that is producing IFN-γ in response to the peptide stimulation cannot be distinguished by this assay method. Theoretically, these peptides can be presented in the context of class I or class II MHC, thus stimulating both CD8⁺ and CD4⁺ T cells within the same splenocyte preparation.

In these assays the number of antigen-specific spots were usually >10-fold more than the number in control wells. IFN-γ producing cells were detected in splenocyte preparations from VR6368-vaccinated mice stimulated with either of the peptide pools, but approximately three times as many spots were detected in response to Pool I than to Pool II. Few to no spots were produced by splenocytes of gB-vaccinated mice in response to stimulation with either of the peptide pools.

These data demonstrate that the HCMV DNA vaccine component pp65 was expressed in vivo at levels sufficient to induce cellular immune responses, either when it was administered alone or in combination, in the VF-P1205-02A formulation.

Example 8 Confirmation of Immunogenicity Plasmids Encoding Human CMV Antigens

General Experimental Procedure

The experimental procedure for the following example is as described above, with particular parameters and materials employed as described herein.

Plasmids

As described above, constructs of the present invention, VR6365 and VR 6368 were constructed by inserting the appropriate inserts into the expression vector VR10551, and were formulated with poloxamer formulation VF-P1205-02A where noted.

Vaccination Regimen

Groups of nine, 6- to 8-week old female BALB/c mice (Harlan-Sprague-Dawley) received bilateral, intramuscular (rectus femoris) injections (50 μl/leg) containing plasmid DNA encoding pp65, gB, or pp65 and gB with or without VF-P1205-02A on days 0, 21, and 49. Each mouse received 200 μg of DNA per vaccination. For formulations containing a single gB or pp65 coding plasmid, 100 μg of blank DNA (VCL10551), which served as a filler, was included. The effect of the blank DNA was tested by vaccinating mice with 100 μg of the single plasmid DNAs delivered with or without VF-P1205-02A in the absence of the filler DNA. Serum samples were collected prior to the first vaccination (day−1) and after each vaccination (days 20, 48, and 63) and gB-specific antibodies were measured by ELISA.

Recombinant gB Enzyme Linked Immunosorbent Assay (ELISA)

Sera were collected from the vaccinated mice, and anti-gB IgG titers were determined using a recombinant CMV gB Enzyme Linked Immunosorbent Assay (ELISA) as described in Example 7.

The anti-gB IgG titers in sera from mice vaccinated with VCL-6365, either alone or in combination with VCL-6368 are given below:

TABLE 13 Anti-gB IgG Titers Bleed 2 Bleed 3 (Day 48) (Day 63) Log₁₀ mean titer Log₁₀ mean titer Immunogen (range) (range) gB + pp65 in PBS 4.6  4.78 (4.4-4.7) (4.4-5.0) gB + pp65 + 4.7  4.96 VF-P1205-02A (4.1-5.0) (4.7-5.3) gB + neg. 4.98 5.25 control plasmid (3.8-5.3) (4.1-5.6) gB + neg. 4.87 5.14 control plasmid + (4.4-5.3) (4.7-5.6) VF-P1205-02A gB in PBS 4.82 5.15 (4.4-5.3) (4.7-5.6) gB + 4.73 5.1  VF-P1205-02A (4.4-5.0) (4.7-5.3)

Plasmid VCL6365 (gB) elicited the production of gB-specific antibodies in mice that received three injections of the plasmids either alone or in combination. All mice vaccinated with VCL6365 had detectable anti-gB IgG titers after two injections. These data confirm the immunogenicity of the gB plasmid product in vivo when VCL6365 is delivered in combination with VCL6368 in the VF-P1205-02A formulation.

Example 9 Plasmid Encoding Human CMV IE1 is Immunogenic

General Experimental Procedure

The experimental procedure for the following example is as described above, with particular parameters and materials employed as described herein.

Vaccination Regimen

Mice received bilateral, intramuscular injections into the rectus femoris of the IE1 plasmid VR6250. The total DNA doses as shown below were each in a 100 μl volume in PBS, but was administered as two equal volume injections, one into each rectus femoris muscle of each mouse. The negative control group contained 5 mice and all other groups contained 10 mice. Mice received injections on days 0 and 14. Splenocytes were analyzed for IE1 reactivity by ELISpot assay in which splenocytes were stimulated with a pool of 98 overlapping 15mer peptides (overlapping by 11 amino acids) that span the entire IE1 protein encoded on the VR6250 construct. Splenocytes from the negative control group were harvested on day 24 and were analyzed for non-specific stimulation of IFN-γ secreting T-cells with the IE1 peptide pool. Splenocytes from the groups injected with IE1 DNA were harvested for analysis of antigen specific, IFN-γ secreting, T-cell responses on days 27-29. Two spleens from each group were pooled for the assay. Two pools from each group were analyzed on days 27 and 28, one pool from each group was analyzed on day 29. The values reported below represent the average of 5 splenocyte pools per experimental group.

IFN-γ ELISpot Assay

T cell responses to the DNA vaccines were determined by quantifying the number of splenocytes secreting IFN-γ in response to antigen-specific stimulation as measured by IFN-γ ELISpot assay. ImmunoSpot plates (Cellular Technology Limited, Cleveland, Ohio) were coated with rat anti-mouse IFN-γ monoclonal antibody (BD Biosciences, San Diego, Calif.), and blocked with RPMI-1640 medium. Splenocyte suspensions were isolated from individual vaccinated mice and added to ELISpot plates at 1×10⁶ or 3.3×10⁵cells/well in RPMI medium containing 5 μg/mL of each of the overlapping IE1 peptides as stimulating antigen. Control wells contained 1×10⁶ splenocytes incubated in medium (no antigen). After a 20-hour incubation at 37° C., captured IFN-γ was detected by the sequential addition of biotin-labeled rat anti-mouse IFN-γ monoclonal antibody and avidin-horseradish peroxidase. Spots produced by the conversion of the colorimetric substrate, 3-amino-9-ethylcarbazole (AEC), were quantified by an ImmunoSpot Analyzer (Cellular Technology Limited, Cleveland, Ohio). The results are expressed as spot forming units (SFU) per 10⁶ cells.

TABLE 14 IE1 ELISpot Results DNA & 100 μg 1 μs 3 μg 10 μg 30 μg 100 μg Dose Blank VR6250 VR6250 VR6250 VR6250 VR6250 SFU/10⁶ 6 5 77 289 367 501 cells

The data shows that administering the IE1 plasmid VR6250 induced an antigen specific immune response, and that the immune response was DNA dose dependent. Additionally, this indirectly confirms that the IE1 protein was expressed in vivo.

Example 10 Formulation Selection Studies

The potency of different vaccine formulations was evaluated in two experimental mouse immunogenicity studies using murine CMV M84. Murine CMV M84 is considered a homolog of the human CMV pp65, and thus served as a surrogate for the pp65 antigen. The first study measured lipid dose responses using a fixed quantity of DNA while the second study evaluated clinically relevant doses of DNA by dose escalation.

Formulations

DMRIE/DOPE in a 1:1 molar ration was produced as a lipid film containing 46.2% DMRIE and 53.8% DOPE by weight (5.14 mg total dried lipid). Prior to injection, the dried, mixed lipid film was hydrated in sterile water for injection to form cationic liposomes that were then added to DNA at the appropriate concentration in 2×PBS. DNA was formulated with DMRIE/DOPE as follows:

TABLE 15 DNA Formulations DNA Concentration (mg/mL) DNA:Lipid* 0.5 2:1 1.0 4:1 3.0 10:1  *DNA (assigned MW = 333 gr/mol):cationic lipid molar ratio

For the lipid dose response studies the DMRIE/DOPE formulations listed above were diluted to a final vaccinating concentration of 0.5 mg/mL of M84 DNA. For the DNA dose escalation studies the formulations were not diluted prior to injection.

Poloxamer formulations for the lipid dose response study were produced with 5 mg/mL of M84 DNA, 7.5 mg/mL of CRL 1005, and 0.3 mM of benzylalkonium chloride (BAK) surfactant. Prior to injection, the formulations for the lipid dose response study were diluted to a final vaccinating concentration of 0.5 mg/mL of M84 DNA. In the DNA dose escalation studies, the formulations were produced with 3 mg/mL of the appropriate plasmid DNA, 4.5 mg/mL of CRL 1005, and 0.18 mM BAK. These formulations were not diluted prior to injection.

Vaccination Regimen

Groups of nine, six- to eight-week old BALB/c mice (Harlan-Sprague-Dawley) received bilateral (50 μL/leg) intramuscular (rectus femoris) injections of plasmid DNA formulated with DMRIE/DOPE or CRL 1005 in PBS. Control mice received DNA in PBS alone. All mice were boosted on (approximately) days 21 and 49. Two weeks after the last immunization, splenocytes were harvested from three mice/group/day for three sequential days, and antigen specific T cell responses were measured by IFN-γ ELISpot assay.

Cell Culture Media

Splenocyte cultures were grown in RPMI-1640 medium containing 25 mM HEPES buffer and L-glutamine and supplemented with 10% (v/v) FBS, 55 μM β-mercaptoethanol, 100 U/mL of penicillin G sodium salt, and 100 μg/mL of streptomycin sulfate.

IFN-γ ELISpot Assay

T cell responses to the DNA vaccines were determined by quantifying the number of splenocytes secreting IFN-γ in response to antigen-specific stimulation as measured by IFN-γ ELISpot assay. ImmunoSpot plates (Cellular Technology Limited, Cleveland, Ohio) were coated with rat anti-mouse IFN-γ monoclonal antibody (BD Biosciences, San Diego, Calif.), and blocked with RPMI-1640 medium. Splenocyte suspensions were produced from individual vaccinated mice and seeded in ELISpot plates at 1×10⁶, 3×10⁵, or 1×10⁵ cells/well in RPMI medium containing 1 μg/mL of the appropriate MHC class I-restricted peptide (M84, ²⁹⁷AYAGLFTPL³⁰⁵, (SEQ ID NO:32) Imgenex, San Diego, Calif.), 1 U/mL of recombinant murine IL-2 (Roche, Indianapolis, Ind.). Control wells contained 1×10⁶ splenocytes incubated in medium with IL-2 only (no antigen). After a 20-hour incubation at 37° C., captured IFN-γ was detected by the sequential addition of biotin-labeled rat anti-mouse IFN-γ monoclonal antibody and avidin-horseradish peroxidase. Spots produced by the conversion of the colorimetric substrate, 3-amino-9-ethylcarbazole (AEC), were quantified by an ImmunoSpot reader (Cellular Technology Limited, Cleveland, Ohio). Statistically significant differences between the T cell responses of mice vaccinated with lipid- or poloxamer-formulated DNA and naked DNA was determined using a Student's t-test with α=0.05.

The M84-specific CD8+ T cell responses of mice vaccinated with 50 μg of M84 DNA formulated with DMRIE/DOPE (“DID”) at the DNA:lipid molar ratios indicated, CRL 1005, or PBS alone are given below.

TABLE 16 CD8+ T Cell Responses Mean SFU/10⁶ Splenocytes Vaccine Formulation CD8+ T cells PBS 299 2:1 D/D 243 4:1 D/D 179 10:1 D/D 299 CRL 1005 344

The M84-specific CD8+ T cell responses of mice vaccinated with escalating doses of M84 DNA formulated with DMRIE/DOPE (D/D) at the DNA:lipid molar ratios indicated versus M84 DNA formulated with CRL 1005 or PBS alone are given below.

TABLE 17 CD8+ T Cell Responses Vaccine Formulation Mean SFU/10⁶ Splenocytes (DNA Dose) CD8+ T cells PBS (300 μg) 533 2:1 D/D (50 μg) 184 4:1 D/D (100 μg) 158 10:1 D/D (300 μg) 243 CRL 1005 (300 μg) 416

Example 11 Experiments Employing HCMV Antigens

Vaccination Regimen

Groups of nine, 6- to 8-week old female BALB/c mice (Harlan-Sprague-Dawley) received bilateral, intramuscular (rectus femoris) injections (50 μl/leg) containing plasmid DNA encoding pp65, gB, or pp65 and gB with or without CRL 1005 (the VF-P1205-02A formulation) on days 0 and 13. Each mouse received 200 μg of DNA per vaccination. For formulations containing a single gB or pp65 coding plasmid, 100 μg of blank DNA (VR10551) was added to yield 200 μg of total DNA. Beginning approximately three weeks after the primary immunization (on day 22), splenocytes were harvested from vaccinated mice and pp65-specific T cell responses were measured by IFN-g ELISpot assay. Three ELISpot assays were performed: assay one measured the immune response from a pool of splenocytes from three mice per group and assays two and three measured the immune response from a pool of splenocytes from two mice per group. The immune responses of the additional two mice in each group were not measured in this series of assays.

IFN-γ ELISpot Assay

T cell responses to DNA-encoded pp65 were determined by quantifying the number of splenocytes secreting IFN-γ in response to stimulation with pp65-derived peptides (Bio-Synthesis, Lewisville, Tex.). ImmunoSpot plates (Millipore, Billerica, Mass.) were coated with rat anti-mouse IFN-γ monoclonal antibody (BD Biosciences, San Diego, Calif.) and blocked with RPMI-1640 medium containing 25 mM HEPES buffer and L-glutamine and supplemented with 10% (v/v) heat inactivated FBS, 55 mM b-mercaptoethanol, 100 U/mL of penicillin G sodium salt, and 100 μg/mL of streptomycin sulfate (10% RPMI). Splenocyte suspensions were produced from vaccinated mice, resuspended in 10% RPMI medium at a density of 2×10⁷ cells/mL, and seeded in triplicate wells of two separate ImmunoSpot plates at a density of 5×10⁵ or 2.5×10⁵ cells/well. Splenocytes were stimulated with two separate pools of overlapping pp65 peptides (one pool per plate) that, together, span the entire pp65 protein and should include all possible T cell epitopes. Therefore, the type of T cell (e.g., CD8+ or CD4+) that is producing IFN-γ in response to the peptide stimulation cannot be distinguished by this assay method. Theoretically, these peptides can be presented in the context of class I or class II MHC, thus stimulating both CD8+ and CD4+ T cells within the same splenocyte preparation. The peptide pools contained 68 (pool I) or 69 (pool II) peptides of 15 amino acids each (except one 13 amino acid peptide in pool II), and each peptide was represented at a final concentration of 5 μg/mL in the assay well. Control wells contained 5×10⁵ cells in medium only (no peptide antigen). After a 21-hour incubation at 37° C., captured IFN-γ was detected by the sequential addition of biotin-labeled rat anti-mouse IFN-γ monoclonal antibody (BD Biosciences, San Diego, Calif.) and avidin-horseradish peroxidase. Spots produced by the conversion of the colorimetric substrate, 3-amino-9-ethylcarbazole (AEC), were quantified by an ImmunoSpot reader (Cellular Technology Limited, Cleveland, Ohio). Data are presented as the number of Spot Forming Units (SFU), produced in response to antigen-specific stimulation, per million cells assayed. The antigen-specific stimulation was calculated by subtracting the mean number of spots in wells containing splenocytes incubated in medium alone (the non-specific, background response) from the number of spots in wells containing the identical splenocyte preparation incubated with a pool of pp65-derived peptides. Three replicate wells were used to determine the mean non-specific background response. Each SFU corresponds to one pp65-specific T cell. Due to the small sample size (n=3), a statistical analysis of the difference of the means was not performed.

Experiment 1—See TABLES 18 and 19.

TABLE 18 T Cell Responses to CMV pp65 Peptide Pool I Mean Fold Increase versus DNA Vaccine SFU/10⁶ Cells pp65 + gB pp65 + gB 170 — pp65 + gB + CRL 1005 705 4.1 pp65 + Blank 681 4.0 pp65 + Blank + CRL 1005 780 4.6 gB + Blank 1 0 gB + Blank + CRL 1005 2 0

TABLE 19 T Cell Responses to CMV pp65 Peptide Pool II Mean Fold Increase versus DNA Vaccine SFU/10⁶ Cells pp65 + gB pp65 + gB 80 — pp65 + gB + CRL 1005 208 2.6 pp65 + Blank 374 4.7 pp65 + Blank + CRL 1005 225 2.8 gB + Blank 0 0 gB + Blank + CRL 1005 0 0 Experiment 2

The experiment above was repeated, and although the pp65+gB group had responses to peptide pool I that were 2.4-fold higher than that measured in the study reported in detail above, the results were similar.

TABLE 20 T CELL RESPONSES TO CMV PP65 PEPTIDE POOL I Mean Fold Increase versus DNA Vaccine SFU/10⁶ Cells pp65 + gB pp65 + gB 407 — pp65 + gB + CRL 1005 444 1.1 pp65 + Blank 435 1.1 pp65 + Blank + CRL 1005 762 1.9 gB + Blank ND — gB + Blank + CRL 1005 ND —

TABLE 21 T Cell Responses to CMV pp65 Peptide Pool II Mean Fold Increase versus DNA Vaccine SFU/10⁶ Cells pp65 + gB pp65 + gB 100 — pp65 + gB + CRL 1005 158 1.6 pp65 + Blank 140 1.4 pp65 + Blank + CRL 1005 225 2.3 gB + Blank 0 — gB + Blank + CRL 1005 0 — Experiment 3 Vaccination Regimen

Groups of nine, 6- to 8-week old female BALB/c mice (Harlan-Sprague-Dawley) received bilateral, intramuscular (rectus femoris) injections (50 μl/leg) containing plasmid DNA encoding pp65, gB, or pp65 and gB with or without CRL 1005 (the VF-P1205-02A formulation) on days 0, 21, and 49. Each mouse received 200 μg of DNA per vaccination. For formulations containing a single gB or pp65 coding plasmid, 100 μg of blank DNA (VCL10551) was added to yield a 200 μg dose of total DNA. The effect of the blank DNA was tested by vaccinating mice with 100 μg of the single plasmid DNAs delivered with or without CRL 1005 in the absence of the blank DNA. Splenocytes were harvested beginning day 66 and pp65-specific T cell responses were analyzed by IFN-γ ELISpot as above. Based on previous results, no pp65-specific T cell responses were anticipated for mice vaccinated with gB+blank DNA or gB+blank DNA+CRL 1005. Therefore, these mice were not evaluated in the ELISpot assays. Statistically significant differences between the mean T cell responses of vaccinated mice versus pp65+gB was determined using a Student's t-test with α=0.05.

TABLE 22 T Cell Responses to CMV pp65 Peptide Pool I Mean Fold Increase DNA Vaccine SFU/10⁶ Cells versus pp65 + gB p-value pp65 + gB 783 — — pp65 + gB + CRL 1005 1360 1.7 0.03 pp65 + Blank 1265 1.6 0.02 pp65 + Blank + CRL 1005 1308 1.7 0.03 pp65 1184 1.5 NS pp65 + CRL 1005 1767 2.3 0.01 NS = not significant

TABLE 23 T Cell Responses to CMV pp65 Peptide Pool II Mean Fold Increase DNA Vaccine SFU/10⁶ Cells versus pp65 + gB p-value pp65 + gB 234 — — pp65 + gB + CRL 1005 544 2.3 0.04 pp65 + Blank 496 2.1 0.04 pp65 + Blank + CRL 1005 651 2.8 0.008 pp65 581 2.5 0.02 pp65 + CRL 1005 704 3.0 0.01

Example 12 Vaccine Combinations DNA and Protein Combination

General Experimental Procedure

The experimental procedure for the following example is as described above, with particular parameters and materials employed as described herein.

Vaccination Regimen

BALB/c female mice, 6/group, were injected in each rectus femoris with 20 μg of HCMV bivalent DNA vaccine in a 50 μl volume+/−poloxamer VF-P1205-02A (“02A”), DMRIE:DOPE, (“D/D”) and/or gB protein as indicated below. Plasmid VR6365 encodes HCMV gB, plasmid VR6368 encodes HCMV pp65. Full-length gB protein purified from CHO cells was obtained from Austral Biologicals. (San Ramon, Calif.). Mice received injections on days 0 and 14 and were bled for determination of gB antibody titers on day 13 and day 26. Splenocytes from two mice per group were harvested on days 26, 27, and 28 for pp65 IFN-γ ELISpot analyses (splenocytes from individual mice were assayed, n=6 per group).

TABLE 24 Immunization Schedule Group DNA (total/injection/mouse) A 10 μg VR 6368 + 10 μg VR6365 + 02A B 10 μg VR 6368 + 10 μg VR6365 + 02A + 4.5 μg gB protein C 10 μg VR 6368 + 10 μg VR6365 + 02A + 1.5 μg gB protein D 10 μg VR 6368 + 10 μg VR6365 + 02A + 0.5 μg gB protein E 10 μg VR 6368 + 10 μg VR6365 + D/D + 4.5 μg gB protein F 10 μg VR 6368 + 10 μg VR6365 Recombinant gB Enzyme Linked Immunosorbent Assay (ELISA)

The ELISA for detecting gB specific serum antibodies was performed with 96 well Costar ½ well EIA plates coated with recombinant CMV gB at a concentration of 0.1 μg/well in borate buffered saline (BBS) buffer. After coating with antigen, the plates were sealed and incubated at 4° C. overnight. Plates were washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Non-specific binding was blocked by incubating plates for 1 hr at room temperature with 100 μL of assay buffer (10% fetal calf serum in BBS). Blocking buffer was then decanted and serially diluted sera (diluted in assay buffer) added at 50 μl/well. Plates were sealed, incubated at room temperature for 2 hours, then washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Goat anti-mouse IgG Fc specific secondary antibody diluted at 1:5000 in assay buffer was added at 50 μl/well; plates were sealed and incubated at room temperature for 2 hours. Plates were washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Substrate, consisting of p-nitrophenylphosphate at 1 mg/ml in 50 nM Sodium Bicarbonate buffer, pH 9.8 and MgCl₂ at 1 mM was added at 50 μl/well, plates were sealed and incubated at room temperature for 60 minutes. Absorbance of each well was determined at 405 nm. Endpoint titer=the reciprocal of the last dilution resulting in a mean absorbance value that is greater than or equal to twice the mean absorbance value of background wells.

TABLE 25 Anti-gB IgG Titers and ELISpot Results HCMV gB HCMV gB HCMV pp65 antibody titers antibody titers Group SFU/10⁶ splenocytes Day 13 Day 26 A 368 325 5867 B 576 467 22400 C 451 717 25600 D 260 500 14400 E 523 1800 187733 F 465 75 1867

Adding gB protein to the bivalent gB, pp65 DNA vaccine formulated in poloxamer increased the anti-gB antibody response up to 14-fold vs. the bivalent vaccine alone (bivalent vaccine+02A+1.5 μg gB protein (Group C) vs. bivalent vaccine alone (Group F), p=0.005) and up to 4-fold vs. bivalent DNA in poloxamer (bivalent vaccine+02A+1.5 μg gB protein (Group C) vs. bivalent vaccine+02A (Group A), p=0.01). Adding gB protein to the bivalent DNA vaccine formulated in cationic lipid increased the anti-gB antibody response 101-fold vs. bivalent vaccine alone (bivalent vaccine+D/D+4.5 μg gB protein (Group E) vs. bivalent vaccine alone (Group F), p=0.00006) and 32-fold vs. bivalent DNA in poloxamer (bivalent vaccine+D/D+4.5 μg gB protein (Group E) vs. bivalent vaccine+02A (Group A), p=0.00005). The pp65 response was similar for all groups indicating that combining protein with the bivalent DNA vaccine to improve the antibody component of the response did not decrease the cellular component of the response.

Example 13 Vaccine Combinations Trivalent Vaccine Combination

Vaccination Regimen

Groups of 10 mice were injected in each rectus femoris with 50 μL of PBS containing multiple DNA plasmids as shown below. Plasmid VR6365 encodes HCMV gB, Plasmid VR6368 encodes HCMV pp65, Plasmid VR6250 encodes HCMV IE1, and “blank” refers to an equivalent plasmid backbone but lacking any antigen coding sequence. All DNA was formulated with the “02A” poloxamer based formulation as described in Example 4. Two sets of injections were given on days 0 and 14. Serum was drawn at day 26 for determination of gB antibody titers.

TABLE 26 Immunization Schedule Group Dose (per leg) A 6.6 μgr VR6368 (pp65) + 6.6 μgr VR6250 (IE1) + 6.6 μgr VR6365 (gB) B 6.6 μgr VR6368 (pp65) + 6.6 μgr blank + 6.6 μgr VR6365 (gB) C 6.6 μgr blank + 6.6 μgr VR6250 (IE1) + 6.6 μgr VR6365 (gB) Recombinant gB Enzyme Linked Immunosorbent Assay (ELISA)

Sera were collected from the vaccinated mice according to the regimen described in Example 7 above. Anti-gB IgG titers were determined using a recombinant CMV gB Enzyme Linked Immunosorbent Assay (ELISA), as described in Example 12 above.

IFN-γ ELISpot Assay

Spleens were harvested for analysis of antigen specific, IFN-γ secreting, T-cell responses on days 27-29. Two spleens from each group were pooled for the assay. Two pools from each group were analyzed on days 27 and 28, one pool from each group was analyzed on day 29. Splenocytes were processed and analyzed for pp65 reactivity by ELISpot assay as described in Example 7. Splenocytes were analyzed for IE1 reactivity by ELISpot assay as described for pp65 ELISpot assay except, splenocytes were stimulated with a pool of 98 overlapping 15 mer peptides (overlapping by 11 amino acids) that span the entire IE1 protein encoded on the VR6250 construct. (See Example 3).

TABLE 27 Anti-gB IgG Titers and ELISpot Results Analysis Group A Group B Group C gB antibody titer 18,560 24,320 62,720 pp65 ELISpot 348 231 1 (SFU/10⁶ splenocytes) IE1 ELISpot 218 1 319 (SFU/10⁶ splenocytes)

Earlier experiments showed that administering each antigen encoding DNA alone elicits an immune response in vivo. The present data show that each antigen encoding DNA induces a specific immunological response when combined with other antigens. Thus, combining the antigens and simultaneously administering multiple antigen encoding DNAs allows generation of immune responses to all the antigens simultaneously.

Example 14 Electrically-Assisted Plasmid Delivery

In vivo gene delivery may be enhanced through the application of brief electrical pulses to injected tissues, a procedure referred to herein as electrically-assisted plasmid delivery. See, e.g., Aihara, H. & Miyazaki, J. Nat. Biotechnol. 16:867-70 (1998); Mir, L. M. et al., Proc. Natl Acad. Sci. USA 96:4262-67 (1999); Hartikka, J. et al.; Mol. Ther. 4:407-15 (2001); and Mir, L. M. et al.; Rizzuto, G. et al., Hum Gene Ther 11:1891-900 (2000); Widera, G. et al, J. of Immuno. 164: 4635-4640 (2000). The use of electrical pulses for cell electropermeabilization has been used to introduce foreign DNA into prokaryotic and eukaryotic cells in vitro. Cell permeabilization can also be achieved locally, in vivo, using electrodes and optimal electrical parameters that are compatible with cell survival.

The electroporation procedure can be performed with various electroporation devices. These devices include external plate type electrodes or invasive needle/rod electrodes and can possess two electrodes or multiple electrodes placed in an array. Distances between the plate or needle electrodes can vary depending upon the number of electrodes, size of target area and treatment subject.

The TriGrid needle array, as described herein, is a three electrode array comprising three elongate electrodes in the approximate shape of a geometric triangle. Needle arrays may include single, double, three, four, five, six or more needles arranged in various array formations. The electrodes are connected through conductive cables to a high voltage switching device that is connected to a power supply.

The electrode array is placed into the muscle tissue, around the site of nucleic acid injection, to a depth of approximately 3 mm to 3 cm. The depth of insertion varies depending upon the target tissue and size of patient receiving electroporation. After injection of foreign nucleic acid, such as plasmid DNA, and a period of time sufficient for distribution of the nucleic acid, square wave electrical pulses are applied to the tissue. The amplitude of each pulse ranges from about 100 volts to about 1500 volts, e.g., about 100 volts, about 200 volts, about 300 volts, about 400 volts, about 500 volts, about 600 volts, about 700 volts, about 800 volts, about 900 volts, about 1000 volts, about 1100 volts, about 1200 volts, about 1300 volts, about 1400 volts, or about 1500 volts or about 1-1.5 kV/cm, based on the spacing between electrodes. Each pulse has a duration of about 1 μs to about 1000 μs, e.g., about 1 μs, about 10 μs, about 50 μs, about 100 μs, about 200 μs, about 300 μs, about 400 μs, about 500 μs, about 600 μs, about 700 μs, about 800 μs, about 900 μs, or about 1000 μs, and a pulse frequency on the order of about 1-10 Hz. The polarity of the pulses may be reversed during the electroporation procedure by switching the connectors to the pulse generator. Pulses are repeated multiple times. The electroporation parameters (e.g. voltage amplitude, duration of pulse, number of pulses, depth of electrode insertion and frequency) will vary based on target tissue type, number of electrodes used and distance of electrode spacing, as would be understood by one of ordinary skill in the art.

Immediately after completion of the pulse regimen, subjects receiving electroporation can be optionally treated with membrane stabilizing agents to prolong cell membrane permeability as a result of the electroporation. Examples of membrane stabilizing agents include, but are not limited to, steroids (e.g. dexamethasone, methylprednisone and progesterone), angiotensin II and vitamin E. A single dose of dexamethasone, approximately 0.1 mg per kilogram of body weight, should be sufficient to achieve a beneficial affect.

EAPD techniques such as electroporation can also be used for plasmids contained in liposome formulations. The liposome-plasmid suspension is administered to the animal or patient and the site of injection is treated with a safe but effective electrical field generated, for example, by a TriGrid needle array, or a four needle array. The electroporation may aid in plasmid delivery to the cell by destabilizing the liposome bilayer so that membrane fusion between the liposome and the target cellular structure occurs. Electroporation may also aid in plasmid delivery to the cell by triggering the release of the plasmid, in high concentrations, from the liposome at the surface of the target cell so that the plasmid is driven across the cell membrane by a concentration gradient via the pores created in the cell membrane as a result of the electroporation.

Electroporation Study in Rabbits

Electroporation assisted DNA vaccine delivery was compared to DNA formulated with DMRIE:DOPE or CRL 1005 and DNA in PBS in a New Zealand White Rabbit model using CMV gB DNA. Rabbits (5 per group) were injected in the tibialis muscle at 0 and 28 days with 50 μg DNA/500 μl/leg. Electroporation was performed immediately after injection using the BTX-ECM830 pulse generator with a 5 mm×8.6 mm 4 needle array at 200V (232 V/cm), 60 msec, 2 pulses, and 2 Hz.

Serum endpoint titers were measured at days 2, 14, 28, 42 and 56 by gB ELISA. The ELISA for detecting gB specific serum antibodies was performed with 96 well Costar ½ well EIA plates coated with recombinant CMV gB at a concentration of 0.1 μg/well in borate buffered saline (BBS) buffer. After coating with antigen, the plates were sealed and incubated at 4° C. overnight. Plates were washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Non-specific binding was blocked by incubating plates for 1 hr at room temperature with 100 μL of assay buffer (10% fetal calf serum in BBS). Blocking buffer was then decanted and serially diluted sera (diluted in assay buffer) added at 50 μl/well. Plates were sealed, incubated at room temperature for 2 hours, then washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Goat anti-rabbit IgG Fc specific secondary antibody diluted at 1:5000 in assay buffer was added at 50 μl/well; plates were sealed and incubated at room temperature for 2 hours. Plates were washed 4× with BBS containing 0.1% Tween-20 (BBST) using an automated plate washer. Substrate, consisting of p-nitrophenylphosphate at 1 mg/ml in 50 nM Sodium Bicarbonate buffer, pH 9.8 and MgCl₂ at 1 mM was added at 50 μl/well, plates were sealed and incubated at room temperature for 60 minutes. Absorbance was determined at 405 nm using an automated 96 well plate reader. Endpoint titer=the reciprocal of the last dilution resulting in a mean absorbance value that is greater than or equal to twice the mean absorbance value of background wells.

TABLE 28 Serum endpoint titers Group Pre-bleed Day 14 Day 28 Day 42 Day 56 CRL 1005 140 420 4830 46720 55040 DMRIE: 240 1360 5120 354987 218453 DOPE PBS + 180 79360 221867 2703360 1884160 Electro- poration PBS 115 135 2240 35840 35840

The mean anti-gB titers for the CRL 1005 group were slightly higher (up to 3 fold higher) than the titers for the PBS group, but the differences were not statistically significant at any time point. The mean anti-gB titers for the DMRIE:DOPE group were 2-10 fold higher (p<0.05 at all post-injection time points) than for gB DNA in PBS. Electroporation after injection of gB DNA in PBS increased anti-gB titers 53-588 fold over gB DNA in PBS without electroporation (p<0.05 at all post-injection time points), 34-189 fold over the CRL 1005 group (p<0.05 at all post-injection time points) and 8-58 fold over the DMRIE:DOPE group (p<0.05 at all post-injection time points).

Example 15 Treating Patients Using Compositions Comprising Human Codon-Optimized HCMV pp65 and gB, and Fragments and Variants Thereof

The plasmid immunotherapeutic products are produced according to current FDA Good Manufacturing Procedures (GMP) and are administered to human subjects under an approved Investigational New Drug application.

A. Initial Studies

Thirty-two healthy adults are immunized by i.m. injection with 0.5 mg or 2.5 mg each of plasmid DNA encoding optimized gB and pp65 on separate plasmids at 0, 2, and 8 weeks. Blood samples are drawn preimmunization and at 2, 4, 8, 10, and 16 weeks for immunogenicity studies, including ELISpot assays to measure CD4+ and CD8+ T cell responses and antibody titers for HCMV gB.

B. Administration to Hematopoetic Stem Cell (HSC) Transplant Donors and Recipients

Following the procedures above, healthy HSC donors are immunized with the plasmid compositions at 4 and 2 weeks prior to donation. Immunogenicity assays are performed using blood drawn from the donors at preimmunization, and every two weeks for 16 weeks post immunization. Recipients are divided into two groups. The first group receives the HSC from the immunized donors, but not be immunized themselves. The second group receives the HSC from the immunized donors and are immunized with the same plasmid compositions as the donors approximately four weeks after HSC transplantation, and immunogenicity assays are performed at pretransplantation and every two weeks as above. Immunizations may be repeated every two weeks for both donors and recipients. 

What is claimed is:
 1. An isolated polynucleotide comprising a nucleotide sequence comprising SEQ ID NO:13 and either SEQ ID NO:5, or an isolated polynucleotide comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:6.
 2. The polynucleotide of claim 1, further comprising SEQ ID NO:28 or
 30. 3. A composition comprising: (a) an isolated polynucleotide comprising SEQ ID NO:13 and (b) either an isolated polynucleotide comprising SEQ ID NO:5 or an isolated polynucleotide comprising a polynucleotide encoding the amino acid sequence of SEQ ID NO:6.
 4. The composition of claim 3, wherein the nucleotide sequence encoding SEQ ID NO:6 is human codon-optimized.
 5. The composition of claim 3, further comprising an isolated polynucleotide comprising a polynucleotide encoding IE1, an immunogenic fragment, variant, or derivative thereof.
 6. The composition of claim 5, wherein the polynucleotide comprises SEQ ID NO:28 or
 30. 7. An isolated polynucleotide comprising SEQ ID NO:28 or
 30. 8. A composition comprising a plasmid comprising SEQ ID NO:28, and an isolated polynucleotide comprising SEQ ID NO:5 or an isolated polynucleotide comprising a nucleotide sequence encoding the amino acid sequence of SEQ ID NO:6.
 9. A method of eliciting an immune response to human cytomegalovirus (CMV) in a human or in a human tissue comprising administering an effective amount of the polynucleotide of claim
 1. 10. The method of claim 9, further comprising administering an effective amount of SEQ ID NO:28 or
 30. 